Colby was conceived when Liza had herself artificially inseminated. Colby was supposed to have been Jake Martin's child, but Adam had switched the sperm samples to make sure that Liza's child turned out to be his. Colby's parents had an on-and-off relationship, and Colby was quite close to her father, but when Liza fled Pine Valley -- and Adam -- she took Colby with her. A few years later, Colby returned to town, and was fifteen years of age. She had run away from Liza and stolen a car to get back to Pine Valley.
On Colby's first day back in town, she was the one who found Greg Madden's dead body. She soon set her sights on another newcomer to town, Sean Montgomery, although part of her interest seemed to be her desire to make sure that Sydney Harris didn't get him. On the night of her Sweet 16, she, Sean, and some of the others stole away on the Montgomery yacht, where Colby offered herself up to Sean seemingly to take his mind off Sydney. Although she assured Sean she was fine, Colby instantly regretted her decision.
Colby broke off her relationship with Sean when she realized he had slept with Hannah Nichols. Colby started to have a crush on Frankie Hubbard, but Frankie did not want much to do with Colby. Frankie changed his mind about Colby after they both survived being kidnapped by Rob Gardner. Frankie told Colby they could only be friends, and Colby accepted.
For the Fourth of July weekend of 2008, Colby went up to her father's cabin in the woods with Cassandra Foster and Dre Woods. She got drunk and Dre, who was sober, drove her and Cassandra home. While Dre drove back home, their car ran over Richie Novak's already-deceased body, but they thought they had killed Richie, but Annie had killed him. Colby and her friends kept that night a secret so they would not go to jail. Jesse Hubbard, the new Pine Valley police chief, found out what had happened and had Colby, Dre, and Cassandra arrested. When the autopsy on Richie's body clarified that he had died as a result of a blow to the head and not due to being hit by a car, the charges against Colby and her friends were dropped.
Colby started to be drawn to Pete Cortlandt. Colby suffered an allergic reaction when she sprayed herself with a tainted bottle of Bella perfume. Colby became furious when she found out Pete and her father, Adam, had tainted all the Bella perfume bottles and she broke things off with him. Eventually, Colby reconciled with Pete, and they became closer in the aftermath of Cortlandt Manor burning down and the Cortlandts being broke. Pete and Colby's relationship never developed beyond friendship, and Pete left Pine Valley.
In the spring of 2009, Colby's mother, Liza, returned to Pine Valley. Liza was pregnant, and she wanted to repair her relationship with her daughter before becoming a mother again. Liza claimed Adam had forced her to stay away from Colby, but she never stopped writing to Colby and thinking of her. Colby said she had never received any letters, and Adam claimed it was because Liza did not want to be part of her daughter's life. Colby was torn between her parents, but she began to soften toward Liza and doubt her father when she overheard a conversation between Jake Martin and her mother. Liza and Jake talked about how Jake was supposed to be Colby's father, but Adam had switched Liza's sperm donor sample. Colby confronted Adam and he confessed what he had done.
Colby agreed to get to know Liza, until Liza was named as a suspect in the murder of Colby's Uncle Stuart. Liza was at the Chandler mansion retrieving the letters that proved Liza had tried to contact her daughter. Adam prevented Colby from receiving any of the letters. Colby went to visit her mother and discovered Erica Kane snooping through Liza's belongings. Erica's daughter Kendall was the main suspect in Stuart's murder, so Erica hoped to find evidence to link Liza to the murder. Colby found a stack of letters with her name on it. They were the letters Liza had written to Colby that Adam had withheld. They proved Liza had always loved and thought about Colby when they were apart. Liza was cleared as a suspect in Stuart's murder, and mother and daughter reconnected.
Liza's son was born, and he was named Stuart after Colby's uncle. Colby moved in with her mother to help care for Stuart. Colby learned Stuart was not her biological brother when Bailey Welles, Stuart's birth mother, arrived in town to get custody of her son. Liza confessed that she had lied about her pregnancy. Colby was disgusted by her mother's lie, but she remained with Liza to help her fight Bailey for custody. When Liza realized she did not have any legal claim to Stuart, she gave custody to Bailey, which angered Colby. She believed her mother should have fought harder to keep Stuart.
Although Adam had kept Liza's letters from her, Colby worried about her father. Adam married Annie Novak, a woman who had killed her own brother and had a history of mental instability. Colby was concerned that Annie was only after Adam's money and power. After a seductive dance by Annie caused Adam to be admitted to the hospital, Colby became determined to rid her father of Annie. Over the phone, Colby pretended to be Annie and convinced a doctor from Oak Haven to visit. Colby also caused Annie to doubt her sanity when she placed a tire iron where Annie would find it -- Annie had used a tire iron to kill her brother. Colby's tactics did not work, but eventually, Adam realized Annie did not love him, and he left Pine Valley to be with a woman from his past who truly loved him, Brooke English.
Colby befriended Stuart's father, Damon Miller. He had arrived in Pine Valley to find Bailey, but he did not know he had fathered a child. When Damon was accused of numerous break-ins, Colby defended Damon to everyone, including Bailey, his girlfriend. Liza warned Colby to stay away from Damon, but Colby did not heed her mother's warnings. Colby was in a car that Damon was driving while he was texting, and the car crashed. No one was seriously injured. Damon was diagnosed with ADHD and began to take medication. Bailey and Damon broke up, and Damon learned he was not Stuart's father after all.
Much to Liza's dismay, Colby and Damon dated, and Colby turned down a summer internship in New York to remain in Pine Valley with him. Her mother made it clear she did not approve of the relationship. Colby thought about sleeping with Damon, but she decided to wait when she realized sleeping with Damon was more about punishing her mother than her feelings for him. When Damon began acting suspiciously, Colby suspected Damon was cheating on her. Liza fueled Colby's mistrust of Damon and planted more doubt in Colby's mind, but Colby still turned to Damon and slept with him after Adam cancelled his plans to spend time with his daughter.
Colby found out Liza had switched Damon's ADHD medication so he would act impulsively; Colby ordered Liza out of her life. Liza claimed she was protecting Colby by exposing who Damon really was, a man Colby could not count on. Colby remained with Damon even though he decided to stay off his medication. Damon and Colby made a new friend, Asher Pike, when he saved Colby from falling through a rooftop railing. Asher convinced Damon to go back on his medication, and Asher moved into the Chandler mansion when J.R. hired him. On Damon's insistence, Colby went with Asher to a party at the Yacht Club, hosted by Caleb Cooney. Asher and Colby bonded when they witnessed an argument between Ryan Lavery and David Hawyard minutes before David was murdered.
Asher helped J.R. take down Caleb Cooney. When Asher confided to Colby that Caleb was his father, Colby urged Asher to pursue a relationship with his father. As Asher and Colby became closer, Damon and Colby drifted apart. Damon witnessed a kiss between Colby and Asher, and he broke up with Colby. When Colby found Damon, she told him she wanted to be with him, but it was too late. He had already slept with someone else. Damon decided to leave Pine Valley to attend school in California.
Colby placed herself in danger when she taped a conversation between Annie and J.R., in which Annie confessed she had knocked Marissa out. Annie found out Colby had the tape, so Annie followed Colby to the cottage and handcuffed her to a table, Asher found her and rescued her. Liza was extremely concerned about Colby, and the pair briefly reconciled. Liza planned to press charges against Annie for harming Colby. The mother-daughter reconciliation ended soon after when Liza confessed she was the woman Damon had slept with the night he broke up with Colby.
Asher confessed he had known about Liza and Damon, so Colby pushed him away as well. Colby turned to the Internet to express her feelings through a video blog. Her blog followers were outraged by what her mother had done. Colby forgave Asher when he was injured in a quarry explosion and she encouraged Asher to move back to the Chandler mansion to recover when his father suggested he move in with him. Asher decided to return to the Chandler home and Colby told him she would spend less time on her blog and more time on the things that mattered in life, although that did not extend to repairing the relationship with her mother.
Colby and Asher flirted with one another and soon declared themselves officially a couple. Colby also befriended a new maid J.R. had hired named Maya Mercado. Shortly after Asher and Colby started dating, Asher ended their relationship. He admitted he had developed an addiction to pain pills and needed to be alone to straighten out his life. Asher claimed he wanted to be a person worthy of Colby and she encouraged him to take care of what he needed to because she looked forward to seeing the person he would be. After Asher moved out, she expressed her feelings in her blog.
While Asher worked to get his life back on track, J.R.'s life was imploding and Colby was concerned for her brother. J.R. was fired from his position at Chandler Enterprises and he lost custody of his son. Colby tried to prevent J.R. from drowning his sorrows in alcohol but she was unable to help him. She reached out to her mother and asked her to help J.R. regain custody of his son.
Colby reached out to her father and asked for his help when she learned the Chandler mansion was in foreclosure. When Adam did not immediately return to Pine Valley, Colby decided to lean on her mother instead and moved in with her. Even though she was not thrilled with her mother, she gave her credit for at least being there for her. Colby also appreciated that Liza allowed Colby's friend Maya and her daughter to temporarily move in with them. Colby forgave her mother and gave her another chance to be a part of her life.
Colby's fresh start with her mother aligned with the start of a new semester at Pine Valley University. Colby and Liza were at Krystal's when Asher stopped in. Colby and Asher both admitted that they missed each other and decided to give what they had started another chance. Asher also shared that he re-enrolled at the university and was signed up for the same classes as Colby.
In the final days before the Chandler mansion was foreclosed upon, Brooke and Adam returned to Pine Valley. As the Chandler family struggled to say good-bye to their home they received joyous news. Colby's presumed-dead Uncle Stuart was alive, thanks to an experimental medical procedure performed by David Hayward. The good news continued when Brooke shared that she had purchased the Chandler mansion and Stuart was scheduled to be released from the hospital later that day. Colby decided they should throw a party at the mansion to celebrate all the good news.
The news about the party spread and many Pine Valley residents were present at the mansion to welcome Stuart home from the hospital. During the party, Adam proposed to Brooke and she accepted. The toasting and celebrating continued as a shot rang out.
Time advanced five years between the final episode on ABC and the first episode of Prospect Park's online version.
Colby spent time in Europe but returned five years later after J.R. had awoken from the coma he had been in since the party five years earlier. J.R had shot and killed David's daughter Marissa. Afterwards, David retaliated and shot J.R.
When Colby returned, she was pleasantly surprised to run into her childhood friend Pete Cortlandt. Pete had grown into a handsome and successful entrepreneur and they ended up in bed together. The next morning, Pete's mother Opal walked in on them and warned Colby to stay away from her son. Colby ignored Opal's warnings and hoped that her night with Pete was the start of something. Pete explained to Colby that he was only interested in being friends with benefits but never responded to any of Colby's offers for benefits after their one night together.
Meanwhile, Colby learned that Adam had left his fiancée Brooke English in charge of Chandler Enterprises while he handled business abroad. When Brooke refused to supply Colby with money and instead suggested that Colby work to earn a paycheck, she was offended and blamed J.R. for losing his position at the head of the company.
Colby deduced that Pete's lack of interest in her was related to his feelings for a girl named Celia Fitzgerald. Colby and Celia worked together at Chandler's Media division for "Talk Tempo." Colby sensed that Celia was a virgin and flaunted her sexual relationship with Pete. Colby made it seem as though she and Pete were spending the night together on a frequent basis when Colby was actually spending time in David Hayward's bed. David supplied Colby with the money she needed to compensate for drugs she had stolen. David insisted he wanted nothing in return and Colby acknowledged that he enjoyed bedding J.R.'s sister and Adam's daughter but she did not care. In return, David ignored Colby's interest in Pete.
Despite the casual nature to Colby's time with David, he offered her comfort when she was shaken by the trauma her friend Cassandra Foster had endured. Cassandra had been kidnapped by Russian sex traffickers and was raped and forced into pornography. When Cassandra learned that she was pregnant, Colby supported her decision to abort the pregnancy and promised to be there for her friend.
Colby feigned friendship with Celia as they planned a gala to launch "Talk Tempo" and benefit the Miranda Center. The event also included a bachelor auction and Colby intended to buy an evening with Pete. As the event neared, Colby sabotaged Celia's dress and tried to make her feel inferior. However, an anonymous caller won the bid for Pete on Celia's behalf. Colby was outraged by the turn of events and schemed with Pete's mother Opal to ruin Pete's date. Opal and Colby unleashed a skunk and it sprayed Celia as they had hoped. Nevertheless, the scheme did not work as the ordeal with skunk brought Pete and Celia closer.
After the gala, Colby and David parted ways as friends although she suspected that David had ruined J.R.'s attempt to redeem himself at Chandler Enterprises. David warned Colby against rallying for her brother but she ignored his advice. Instead, she encouraged J.R. to fight for his position within the company.