Dan Stewart married Susan Burke while still in medical school. Susan was ambitious and pushed her husband into becoming a surgeon because it was the most lucrative field. Though they tried to keep their marriage secret from their families, the truth came out when Susan suffered a miscarriage. Soon after, Dan found himself drawn to the more easy-going Liz Talbot. Susan tried everything to keep Dan away from Liz and married to her, including setting up Liz with Dan's brother, Paul. However, Susan's ambitious nature, and the way she favored doing what was good for her career rather than what was right, wore on Dan and he started confiding more and more in Liz. When Dan finally asked for a divorce, Susan refused, and then took her mother-in-law, Ellen's advice, to start a family and seduced Dan. Needless to say, when Susan announced her pregnancy, Dan was less than pleased and became increasingly morose, especially when Liz married Paul! Becoming angry and bitter, Dan got in an argument with Susan that caused her to fall down the steps and lose her baby. Afterwards, she milked her recovery for all it was worth, determined to keep Dan by her side. Later, Susan learned that Dan and Liz had an affair right before Liz married Paul. Knowing that Dan wanted a divorce, Susan threatened that if he divorced her, she'd name Liz as the co-respondent. Though Susan hoped to make herself more desirable to Dan, by flirting with John Dixon, the plan failed, so Susan threatened to tell Paul about Dan and Liz's affair since she suspected that Liz was carrying Dan's baby. Resigned to his fate, Dan let Susan seduce him in a weak moment and they had a child, Emily. Soon after, Susan grew tired of Dan and finally gave him a divorce.
The reason for Susan's change of heart was Dr. Bruce Baxter, an ambitious man who had zero tolerance for children. Susan soon married Bruce and left Emily with Dan, but when Susan learned that Bruce had had a vasectomy, and thus they'd never have children, she annulled the marriage. At this point, Susan became bitter and resented Dan's happy marriage to Liz. One day, after an argument with Liz, Susan accidentally left the baby gate open at Dan's house. Liz saw Betsy teetering at the top of the stairs and in the rush to shut the gate, Liz tripped on the stairs and died.
Susan's life spiraled out of control when Dan took Emily out of the country to avoid a custody fight. By the time Dan returned to town, Susan was drinking heavily and was declared an unfit mother. Susan's drinking became so bad that she was fired from the hospital. The worse Susan's life got, the more she drank. Soon, she became a bar hopping drunk with her close buddy, and lover, Kevin Thompson. Meanwhile, Dan was falling in love with John’s wife, Kim, and John was using Susan's drinking to guilt Kim into forgetting about being with Dan. Susan was also trying to get Dan to return to her, but to no avail. Finally, one day, Susan was at Dan's to pick up some of Emily's things, and overheard a message from Kim telling Dan she loved him! Not wanting Dan to know, Susan pocketed the tape. However, instead of Dan turning to Susan, he turned to Kim's former sister-in-law, Valerie Conway. Susan ended up confiding the truth about what she did to both John and Kevin. John became so distraught about losing Kim (who was pregnant with his child) that he began drinking heavily and acting erratically, leaving Susan afraid that he'd blurt out the truth. However, the most harm came from Kevin. Kevin was friends with Valerie and, not wanting to see her get hurt by entering into a doomed relationship, he told Susan to tell Kim the truth or he would. Her back against the wall, Susan finally told the truth and lost Dan to Kim. Meanwhile, Susan's drinking continued to be out of control until she was finally fired from the hospital.
Unfortunately, Susan made things worse by showing up at the review board drunk and accusing the hospital administrator of having a vendetta against her. Susan finally hit rock bottom when she was arrested for drunk and disorderly conduct. Believing he was helping her, Kevin let her stay the night in jail. Though Susan angrily confronted him about it, Kevin was determined to get her to stop drinking and took her to a cabin to dry out. It worked and Susan finally decided stop drinking and rebuild her life. Unfortunately for Kevin, Susan decided that the best way for her to rebuild her life was to break off with him since she felt that they weren't good or each other.
Susan's determination to rebuild her life was rewarded and she was re-instated at the hospital. There she put all her efforts into helping a terminally ill patient named Mark. Though Mark was inspired by Susan's courage in her fight to stay off the bottle, working on his case put an emotional toll on Susan. Her former father-in-law, David Stewart, took note and railed at Dr. Alex Keith for allowing Susan to work herself too hard. In the end, Susan stayed sober and Mark was transferred back home where he died. In 1979, when Kevin died in an accident, and Dan died of a terminal illness, Susan took Emily and left town.
Susan returned to town years later with Emily. One day, Susan injured her back in fall and soon found herself addicted to prescription painkillers. Help from her friend, Bob Hughes, led to a one-night stand. On the plus side, Susan was instrumental in getting Casey Peretti to go to New York to propose to her friend, Lyla. Later, Susan found love with the much younger Larry McDermott. Though she was concerned about the age difference, they married and had a child through invitro-fertilization. Though the child, Alison, was technically Emily's since she donated the egg, Susan carried it to term and asked that Alison never be told the truth about the circumstances of her birth. Unfortunately, the marriage ended when Larry took a job in Chicago and had an affair. Angry, Susan dropped the McDermott from Alison's name and raised the girl away from her father.
After spending years worrying about Emily's problems, things got rather complicated when Alison turned 17. By now, Alison was a selfish teenager, though Susan refused to see it. Despite Susan’s refusal to allow Emily to tell Alison the truth about her parentage, Alison found out anyway and rebelled. Though Susan refused to listen to Emily's concerns about Alison, it appeared that she was wrong when Alison admitted to arson in order to get the attention of the boy she loved, Aaron Snyder. Standing by her daughter when Alison finally confessed to the police, Susan supported her and wouldn't allow her to use manipulations to get out of her sentence. About the time that Alison was released early, Susan would find love again with Dr. Eric Decker, someone she met at a medical convention. Very soon after meeting Ric, Susan allowed him into her home despite some initial objections from Alison. Having been lonely for a long time, Susan welcomed the attention Ric gave her. Soon after, Ric became a suspect in a slew of murders committed at Memorial. Despite the evidence against him, Susan refused to acknowledge the possibility and accepted his marriage proposal. Despite Alison's and Emily's concerns, Susan married Ric, overlooking his odd behavior at their wedding when he began hallucinating. Angry that both her daughters suspected Ric was the killer, Susan threw Alison out and told Emily she'd disown her if she didn't accept Ric. However, Susan's resolve began to crumble when she learned that Ric lied to her about being home with her one night when Alison claimed he wasn't. Confused about why he lied, Susan demanded an answer. In a corner, Ric confessed that he suffered from anxiety attacks and persuaded Susan to run away with him so he could get help. Blinded by love, Susan refused to tell Emily where she was going. The next day, Susan was horrified to see a headline in the paper saying Alison had been murdered and was last seen in the company of Dr. Ric Decker!
Realizing she was wrong all along, Susan confronted Ric who finally confessed that he was the killer! Horrified, Susan ran back to Oakdale where she discovered that the newspaper article was just a ruse to smoke out Ric. Alison was alive! Not long after, Ric was apprehended after holding both Alison and Susan hostage. At the police station, Rick confessed to the murders and of initially using Susan so that he could get a job at Memorial. Though he admitted that he did fall in love with her, a bitter Susan wrote him out of her life and reunited with her daughters. Although, the stress of the situation almost caused Susan to go back to drinking, she fought the urge and was determined to go on with her life.
As Susan’s life started to settle down again, her daughters’ were getting out of control. Especially Emily, who became so unhinged after a failed romance with Paul Ryan that she ended up shooting him and then kidnapped Dusty Donovan. From that point, Susan became very protective of Emily and blamed Paul for the problems in her life. Meanwhile, Alison returned to town after two years and seemed to be in constant conflict with Emily. Dusty seemed to be hanging around as well and when Susan caught him in a kiss with Emily, she assumed they were having an affair. Finally, Alison suddenly moved out but not before informing Susan that Emily had worked as a prostitute. Susan confronted Emily, who confessed that she lost herself and did work as a high priced call girl. However, she made it clear that she was not doing that anymore. Emily then came back with a revelation of her own---she and Dusty had found Alison doing porn movies in Las Vegas. Not only that, Ali was a meth addict. Soon after, Dusty rescued Alison from Las Vegas and this time she was ready to turn her life around. Unfortunately, things got complicated when Emily learned that Dusty and Ali had made love in Las Vegas. The stress of everything that had happened without her knowing got too much for Susan and, one da,y she began drinking again. It didn’t take long for Ali to smell it on her breath and she and Dusty confronted Susan at the hospital. Alison urged her mother to go to an AA meeting. Susan complied and quickly confessed to Bob. Though she offered to resign, Bob was willing to argue for a suspension instead. Meanwhile, months later Susan tried to dissuade Alison against donating an egg for the infertile Gwen Munson but Alison was adamant. However, it quickly became a moot point when Gwen miscarried the baby.
Afterward, Susan focused on her professional life and dispensing advice to her daughters.