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 Fuller [2013, 2014]
Drove off with Wyatt Fuller's camper 
Shoved Rick Forrester to the ground 
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, but Hope Logan helped Liam adjust, 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 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, stopping Hope from accepting Oliver's marriage proposal.
When Hope wanted to stay a virgin util her wedding night, Liam became frustrated and publicly proposed to Hope during a showing for her Hope for the Future collection. Liam saved Steffy, who fell in her bathtub and nearly drowned; Steffy fell for Liam and let him know she was sexually available by kissing him. Liam soon found Hope's engagement ring on his mantel and a phone message breaking their engagement; Liam offered Steffy the ring and took her to Aspen. Liam married Steffy in a surprise wedding, later finding out that Hope had seen them kissing and followed Liam to Aspen to make things right, but was locked in a gondola by the disapproving Bill, forcing her to watch Liam and Steffy's nuptials.
Liam wanted to return to Hope but felt obligated to stay with Steffy after she was thrown from an ATV in Cabo San Lucas and diagnosed with a blood clot in her brain. Liam forgave Steffy when he learned how Steffy had helped Bill keep Liam and Hope apart in Aspen and Mexico, but Liam was horrified to discover that 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 was pleased when Hope relaxed her stance on waiting for marriage and moved in with him, but he became concerned when she froze up in bed. Liam saved the increasingly erratic Hope from drowning in the Forrester pool, learning she'd been doubling up on antianxiety medication 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.
Liam and Hope planned to marry in Puglia, Italy, but Hope was a no-show, and Liam found a note saying she couldn't go through with it. Liam kissed Steffy and professed his love until Hope explained that she had been delayed by the sudden appearance of her estranged father, Deacon Sharpe. Liam married Hope anyway but remained conflicted about Steffy. After Hope saw a video of Liam and Steffy kissing that he'd accidentally recorded on his iPad, Liam agreed to a "do-over" wedding with Hope but partied with Steffy the night before, showing up for the ceremony with dyed hair and a tattoo. Hope rejected Liam, who found his way back to Steffy.
Liam raged when he learned how many people had plotted against him: Hope's brother, Rick Forrester, had told Hope that Liam and Steffy kissed the night before Liam's "do-over" wedding, and it came out that Bill had sprung Deacon from jail for the express purpose of keeping Liam from marrying Hope in Italy. Liam punched Rick, then disowned Bill, softening when Bill stabbed himself in the chest with his sword necklace; Liam didn't know Bill cushioned the blow with his money pouch.
Liam was intrigued when Hope wanted to win him back, and agreed when Steffy advised him to get Hope out of his system. Liam wanted time to think, but found himself in the middle of a surprise wedding to Hope thrown by her mother, Brooke Logan. Liam nearly married Hope until Steffy arrived with news she was carrying his child. Liam wed Steffy in a unique ceremony where she roared down the aisle on a motorcycle; Liam asked Steffy to stop riding until after their baby was born, desolate when Steffy was in an accident and miscarried. Liam couldn't understand when the depressed Steffy decided to move to Paris alone; Liam followed and learned that Steffy had become infertile. When Steffy wouldn't come home, Liam proposed to Hope, who had gotten involved with Wyatt Fuller. Liam was shocked when Wyatt turned out to be his half-brother through a fling between Bill and Wyatt's mother, Quinn Fuller.
Again having to wait for a divorce from Steffy to become final, Liam punched Wyatt for kissing Hope, then invited Hope to move in with him. Liam objected when Hope chose Quinn's company, Quinn Artisan Jewelers, to create accessories for Forrester because it meant Hope would be working with Wyatt. Liam made a tribute video to Steffy as a way of saying goodbye, but Hope saw it; Liam and Hope learned that Quinn had hacked into Liam's e-mail and sent the video to push Hope toward Wyatt. Liam gave Hope an ultimatum about marrying him; on their wedding day, Liam was shocked when Steffy arrived and announced she'd had a procedure which now allowed her to have children. Liam wished Steffy well but said his future was with Hope, who took off for Hawaii with Wyatt. Liam followed and explained his conversation with Steffy, and that Quinn had brought Steffy to town to split Liam and Hope, but Liam flew back to L.A. alone.
Mistrustful of Wyatt, Liam discovered security footage that showed Wyatt pocketing a rare diamond on loan to Forrester, then planting it on jewel thieves to impress Hope. Liam crashed Wyatt and Hope's camping trip with the news, but only after Liam escaped an elevator in which Quinn trapped him. Liam was surprised when Hope ultimately stayed with Wyatt, and remained oblivious when young Aly Forrester, Hope's childhood friend, developed a crush on him.
Liam, who had Bill as a houseguest, walked in to find Bill and Quinn engaged in raucous S&M sex. Later, hearing Hope had a pregnancy scare with Wyatt, Liam lured Hope to Wyatt's camper and drove off with her inside, asking Hope to consider dating both him and Wyatt. Liam found himself trapped in the Forrester steam room by Quinn, and punched by Wyatt for calling Quinn a "vile, manipulative, evil bitch." Liam was glad when Hope became his exclusively, but Liam had to bear the wrath of Quinn, who stabbed Liam in the neck with his sword necklace and tormented Liam to the point he fell and sprained his ankle. Liam nearly died when Quinn tried to impale him with a real sword; Wyatt saved Liam and the half-brothers bonded over the ordeal.
Liam walked out on Hope when she accepted the Hope for the Future diamond from Wyatt during a press conference. Liam agreed to meet and marry the conciliatory Hope in Paris, where she was doing a photo shoot involving the diamond; Liam ended up having to save jewelry designer Ivy Forrester, who fell into the River Seine, and by the time he got to Hope's meeting place, Hope was gone. Liam explained everything when he learned that Hope had married Wyatt instead, but got nowhere convincing Hope to come back to him. Liam slowly took an interest in the Australian Ivy, whose visiting father, John Forrester, questioned Liam about his intentions.
Liam hoped he and Hope would reunite after learning that Quinn had pushed Ivy into the Seine to stop their wedding, but Liam was rocked when Hope revealed she and Wyatt were expecting a baby. Liam traveled to Amsterdam for the launch of Ivy's jewelry line, professing his love for her during a romantic boat ride. But Liam knew that Quinn was obsessing on Hope's baby, and arrived to find Hope at the bottom of a steep flight of stairs. After Hope miscarried, she and Liam admitted they would always love each other; Hope left for Milan, and Liam began concentrating on Ivy.
Outraged that new Forrester CEO Rick was tormenting Ivy, Liam cooked up a takeover plot that would involve Bill signing his 12.5% stake in the company to Liam. But Liam hit a roadblock when Steffy, who owned a necessary 25%, wouldn't give Liam control unless he left Ivy for her. Liam chose to stay with Ivy, but worked with Wyatt to uncover incriminating information involving Rick's mistress, Maya Avant. Liam and Wyatt learned that Maya was transgender, but before they could decide how to use the information, Bill published Maya's story in his magazines over the brothers' objections. Steffy's father, Ridge Forrester, promised to make Liam vice president of the company if Liam followed through on his takeover plan, which unseated Rick.
With Steffy installed as Forrester's president, Liam found his feelings for her resurfacing, although he agreed to marry Ivy because she was in danger of being deported back to Australia. When Ivy learned she actually had dual citizenship and released Liam, he deliberated going back to Steffy. Aly, who had a history of mental illness stemming from the traumatic death of her mother during childhood, died in a violent confrontation with Steffy; Liam broke up with Ivy at Aly's memorial.
Liam defended Steffy when Ivy produced a video that implicated Steffy in Aly's death, though Liam was unnerved that Steffy didn't have a full memory of the incident. Along with Wyatt and Steffy, Liam convinced Ivy to delete the damning video and tried to broker a truce between the feuding cousins. Later, Liam learned that his own cousin, Caroline Spencer, was expecting a baby with new husband Ridge; when Liam stumbled upon information that Ridge had a vasectomy, he was told by Ridge to keep quiet.
Liam proposed to Steffy, but had to tell his fiancée to butt out when she learned that Ivy, who was now seeing Wyatt, had kissed Steffy's brother, Thomas Forrester, behind Wyatt's back. After Steffy and Ivy's argument ended with Ivy being electrocuted, Liam couldn't help thinking of Steffy's connection to Aly's death. Liam gently rebuffed Ivy when she admitted she still wanted a life with him, but, when Wyatt proposed to Ivy and Quinn barged in having overheard Ivy's confession, Liam was forced to tell Wyatt he was Ivy's second choice.
Liam walked out on Steffy after Ivy fell down the stairs following another argument, escorting Ivy on the plane when Ivy wanted to move home. Liam hit his head in the lavatory and woke up en route to Australia with no way of letting Steffy know where he was; when Liam returned home, he found Wyatt in Steffy's bed and broke off his engagement to Steffy. Suffering from dizzy spells, Liam angrily resigned from Forrester but fainted during an argument with Quinn. Liam woke up in Quinn's cabin with no memory except Quinn taking care of him; calling Quinn his guardian angel, the disoriented Liam kissed Quinn's hand, then her cheek.
Liam discovered that their names were Adam and Eve, and that they were married. Liam made love to â€śEveâ€ť, unaware he was bedding his former enemy. As "Adam," Liam listened as Quinn revealed details of a neglectful mother and a child she once lost. Later, Liam answered Quinn's phone and introduced himself as Adam, not recognizing Steffy's voice on the other end. Liam told Quinn that he loved her, though he continued suffering from nausea, dizziness, and headaches.
Liam was desperate to remember more about his life with â€śEveâ€ť, especially after not recognizing their friend â€śJim,â€ť who was really Deacon. Liam found some consolation in a photo album of his supposed wedding to â€śEve.â€ť Liam went on a treacherous hike with Quinn to a cliff overlooking the ocean but ran back to the car for Quinn's inhaler when she had an attack, not knowing that Quinn used the time to push Deacon off the cliff. Liam agreed to travel the world with Quinn, but began having memory flashes of Steffy.
Liam's memories began flooding back when Wyatt burst in and told him who he was. With Wyatt's help, Liam locked Quinn in a closet and was reunited with Steffy. Not having his full memory back, Liam believed he was still engaged to Steffy and planned their wedding, receiving a shock when Steffy told Liam she had married Wyatt in his absence. Liam returned to work at Forrester and informed Wyatt that he wanted his life -- and Steffy -- back.