Kissed Steffy Forrester while engaged to Hope Logan 
Tore up Steffy Forrester's annulment papers and kept it a secret from fiancee Hope Logan 
Kissed Steffy Forrester on day of wedding to Hope Logan 
Punched Rick Forrester 
Kissed Hope Logan while committed to Steffy Forrester 
Punched Wyatt Spencer [2013, 2014]
Drove off with Wyatt Fuller's camper 
Shoved Rick Forrester to the ground 
Kissed Steffy Forrester despite her being married to Wyatt Spencer 
Computer tech Liam Cooper arrived in Los Angeles following the death of his mother, Kelly Cooper, who said he could find his father at design house Forrester Creations. Both Thorne Forrester and publishing magnate Bill Spencer, Jr. had dated Kelly, so they submitted to a DNA test; Liam chafed when the more aggressive Bill turned out to be his father. Liam made the adjustment with the help of Hope Logan, which led to a sweet romance, during which Liam fended off the advances of Hope's rival, Steffy Forrester.
After a misunderstanding with Hope, Liam got drunk at a party and hit his head, waking up next to Amber Moore, who soon claimed she was carrying Liam's baby. Liam and Hope went through a dizzying array of breakups and makeups trying to decide what was best for the child, and Liam faced competition from Hope's ex-boyfriend, Oliver Jones. Liam suffered a concussion in an explosion caused by Amber's pilot light; months later, Liam realized he'd been duped when Amber gave birth to an African-American baby, barely stopping Hope from accepting Oliver's marriage proposal.
When Hope wanted to stay a virgin until her wedding night, Liam became frustrated and publicly proposed to Hope during a showing for her Hope for the Future fashion collection. Liam saved Steffy, who fell in her bathtub and nearly drowned; Liam resisted when Steffy became amorous and let him know she was sexually available. After Liam kissed Steffy and came home to find Hope's engagement ring on his mantel, Liam gave the ring to Steffy and took her to Aspen, exchanging vows with her there during a surprise wedding.
Liam later found out that Hope had seen him kissing Steffy but followed him to Aspen to make things right, only to be locked in a gondola by a disapproving Bill and forced to watch Liam's wedding. Liam wanted to return to Hope but felt obligated to stay with Steffy, who was suffering from a life-threatening blood clot as the result of being thrown from an ATV in Cabo San Lucas. Though Liam forgave Steffy for conspiring with Bill in Aspen, Liam raged upon learning Bill had faked Steffy's MRI to manipulate him into staying with Steffy. Liam asked Steffy for an annulment and was about to marry Hope until Steffy announced she wanted to hold out for a proper divorce.
Liam moved Hope in with him, but was concerned when she became increasingly erratic after freezing up in bed. Liam saved Hope from drowning in the Forrester pool, upset to find she'd been taking excessive doses of antianxiety pills so she could make love to him. After Hope crashed into Steffy on the slopes of Aspen, the furious Liam tended to Steffy and tore up the annulment papers she'd finally agreed to sign.
About to marry Hope in Puglia, Italy, Liam found a note from the absent Hope which declared she couldn't go through with it. Liam professed his love to Steffy, relenting when Hope explained she had been delayed by the sudden appearance of her estranged father, Deacon Sharpe. Liam finally married Hope, but after she saw a video of him kissing Steffy he'd accidentally taken with his iPad, Liam agreed to give Hope a "do-over"Ě wedding. But Liam partied with Steffy the night before and showed up for Hope's ceremony with dyed hair and a temporary tattoo, so Liam found himself single again, soon finding his way back to Steffy.
Liam raged to learn that Hope's brother, Rick Forrester, had told Hope that Liam kissed Steffy before the do-over, and that Bill broke Deacon out of jail to ruin the Puglia wedding. Liam punched Rick and disowned Bill, relenting when Bill stabbed himself with his sword necklace; Liam didn't know Bill cushioned the blow with his money pouch. When Hope wanted Liam back, Liam asked for time to think but walked into a surprise wedding that Steffy interrupted with news she was pregnant. Liam married Steffy instead in a unique ceremony where she roared down the aisle on a motorcycle; Liam asked Steffy to stop riding until after the baby was born and was inconsolable when Steffy had an accident and miscarried. Liam questioned why Steffy suddenly moved to Paris until he followed her there and learned that the accident had left her barren.
Liam tentatively moved on with Hope, who was also seeing Wyatt Fuller. Liam was shocked to learn that Wyatt was his half-brother through a fling Bill once had with Quinn Fuller, but that didn't stop Liam from punching Wyatt for kissing Hope. Liam scrambled to explain when Hope saw a video tribute Liam made for Steffy, realizing Quinn had hacked into his e-mail in an attempt to push Hope toward Wyatt. Getting Hope down the aisle, Liam was surprised when Steffy arrived, telling him she could have children again thanks to a procedure she had done overseas. Liam wished Steffy well but had to follow Hope to Hawaii when she ran off with Wyatt; though Liam explained Quinn had convinced Steffy to see him, Liam flew home alone.
When Liam found security footage that showed Wyatt pocketing the rare "Hope for the Future"Ě diamond he said he'd rescued from jewel thieves, Liam crashed Hope's camping trip with Wyatt and exposed him, but only after he managed to escape being trapped in an elevator by Quinn. Liam cringed when he came upon houseguest Bill having raucous S&M sex with Quinn. Later, after hearing about Hope's pregnancy scare, Liam lured Hope into Wyatt's camper and drove off, trying to convince Hope to date both of them. Having been locked in the Forrester steam room by Quinn, Liam won Hope when Wyatt socked him for calling Quinn an evil bitch.
Liam barely survived when Quinn stabbed him with his sword necklace, then tried to impale him with the real thing. Though Liam was grateful to Wyatt for saving him, their brief truce ended when Wyatt presented Hope with the HFTF diamond at a press conference. Liam walked out on Hope, but agreed to meet her in Paris to get married under the Eiffel Tower. En route, Liam was delayed saving jewelry designer Ivy Forrester, who had fallen into the River Seine. After Hope married Wyatt instead, Liam learned Quinn had pushed Ivy into the Seine on purpose, but Hope decided to stay with Wyatt because she was carrying his baby, so Liam moved on with Ivy during a romantic trip to Amsterdam and talked to Ivy's father, John Forrester, about his intentions. Liam found the pregnant Hope at the bottom of a staircase after she argued with the obsessive Quinn; Liam and Hope admitted they'd always love each other after Hope miscarried and decided to move to Milan.
Enraged that new Forrester CEO Rick was tormenting Ivy, Liam devised a takeover plot involving his father's 12.5% stake in the company, but Steffy would only contribute her 25% if Liam came back to her. Instead, Liam worked with Wyatt and found out that Rick's mistress, Maya Avant, was transgender; Liam and Wyatt were aghast when Bill published an exposť on Maya over the brothers' objections. Liam became vice president of Forrester when his plan to combine Bill's stock with that of Steffy's family was successful.
Just as Liam's feelings for Steffy resurfaced, Liam agreed to marry the Australian Ivy, who was facing deportation, in name only. Though Ivy's cousin, Aly Forrester, who had a history of mental illness stemming from the traumatic death of her mother in childhood, died in a violent confrontation with Steffy, Liam dumped Ivy at Aly's memorial. Liam defended Steffy against Ivy, who was trying to blackmail Steffy with a video that made it seem Steffy had killed Aly. After Liam brokered a truce between the feuding cousins, Liam stumbled upon information that his own cousin, Caroline Spencer, was not carrying the child of her husband, Ridge Forrester, but Liam agreed to keep quiet.
Liam withdrew from Steffy as she insisted on telling Wyatt that new girlfriend Ivy was kissing her brother, Thomas Forrester, behind Wyatt's back; though Liam had rebuffed Ivy's attempt at a reconciliation, Liam walked out on Steffy after her battles with Ivy left Ivy electrocuted and suffering from a concussion. Liam suffered his own concussion when he escorted the departing Ivy onto her plane and hit his head in its lavatory; when Liam came home dizzy from his inadvertent flight to Australia, he found Steffy cuddling in bed with Wyatt and broke off his engagement to her without explaining why.
Collapsing in the Forrester parking lot and sustaining another head injury, an amnesiac Liam woke up in a cabin to find Quinn taking care of him. Believing Quinn's story that they were married couple Adam and Eve, Liam made love to Quinn and told her he loved her as she confided in him about her neglectful mother and once losing a child. Still combating nausea, dizziness, and headaches, Liam answered Quinn's phone, not recognizing Steffy's voice on the other end. Though happy with "Eve,"Ě Liam wanted to know more about their life together, finding answers in a photo album that displayed doctored wedding photos.
Growing increasingly frustrated about his impaired memory, Liam began having memory flashes of Steffy. Just as Liam was about to travel the world with Quinn, Wyatt rushed in, which gave Liam total recall. Liam escaped when Wyatt helped him lock Quinn in a closet, but Liam was stunned to learn that Steffy had married Wyatt in his absence. Liam had Quinn arrested, but dropped the charges when Quinn's attorney reminded Liam his sexual relations with Quinn had been consensual and that it would be nearly impossible to make his case stick.
Liam subdued an intruder in his home thinking it was Quinn, but it turned out to be the reverend who married Wyatt and Steffy. Liam was sure the reverend was a fraud until Bill confirmed his legitimacy; when Liam refused to give up on Steffy, Bill's threat to cut him off from the family forced him to respect Steffy's marriage. Liam admired Bill's commitment to his own wife, Katie Logan, until Liam discovered the secret love nest Bill was sharing with Katie's sister, Brooke Logan. Liam blasted his father and then turned his attention toward Steffy, who was having a hard time keeping Quinn away from her. Liam was as horrified as Steffy when Quinn romanced Steffy's grandfather, Eric Forrester, yet Liam remained hopeful that Quinn's constant presence would send Steffy running back to him.