Steven Lars Webber is the biological son of Heather Grant Webber and Jeff Webber. When Heather became pregnant, Jeff was still married to Monica and refused to leave his wife for Heather. So Heather went to New York to become a model. She gave birth and sold her baby on the black market. Little did she know, the baby was sold to a couple in Port Charles, Diana and Peter Taylor. Heather had been working for the Taylors as a nanny to their other child and had already tried to sell her baby to them. When Jeff sued Heather for custody of his son, Heather lied and told him the baby had died. They bonded over their son's "death." Jeff then left Monica and married Heather.

But Heather soon discovered that the new addition to the Taylor family, a baby boy they called P.J., was really Steven Lars. She was determined to get her son back and plotted to drive Diana insane. Diana and Peter had made Jeff and Heather the baby's guardians in the event of their deaths. Heather's mother soon grew tired of Heather's games and told Peter the true identity of P.J. Peter then had a heart attack and died. Diana learned the truth as well and feared she would lose P.J. to Jeff. So she tried to seduce him into marrying her. When Diana was found murdered with the name "Anne" scrawled in blood near her body, Jeff suspected Heather of the crime. He divorced her and took Steven out of town with him.

Steven Lars returned to Port Charles as an adult. He was working for John Durant to get to Carly Corinthos. After brief romances, Steven faded into the background after A.J.'s murder and hasn't been mentioned since, nor did he show up for half-sister Liz's wedding.

Steven moved back to Port Charles in December 2009. He had been living in Memphis, working in a hospital trauma unit. Monica wanted Steven to take over as Chief of Staff. Steven jumped at the opportunity to step into the position that had once been held by his grandfather and namesake, Steve Hardy. It was at this time that Steven began going by the shortened version of his name, Steve.

Elizabeth was delighted to have her brother living nearby. She was carrying on an affair with Nikolas Cassadine while engaged to Nikolas' brother, Lucky Spencer. The stress of leading a double-life took a toll on Elizabeth and she suffered a nervous breakdown. Steve was a tower of strength for his little sister. He helped Audrey take care of his nephews, Cam and Jake, while Elizabeth sought treatment at Shadybrook.

Steve continued to watch over his sister after she returned to work and he assigned her to the oncology unit. Elizabeth bonded with a patient named Shirley and came to terms with the end of her marriage to Lucky and learned she was pregnant with either Nikolas or Lucky's child. Steve provided Elizabeth with emotional support when she learned Nikolas was the father of her unborn child.

When Steve was not at the hospital or with Elizabeth, he started spending more time at Jake's bar with Patrick Drake and his wife Robin as well as Patrick's ex-girlfriend from college, Lisa Niles. Lisa was an orthopedic surgeon and Steve hired her to work at the hospital. He and Lisa briefly dated, although he was aware Lisa was using him to make Patrick jealous. They slept together one night but their relationship remained strictly professional afterward.

Lisa set her sights on ending Patrick's marriage to Robin and both Patrick and Robin turned to Steve for help. They asked him to transfer Lisa to another hospital but Lisa threatened to bring forth a sexual harassment suit against Steve. Since he had slept with Lisa, he was unable to grant Patrick and Robin's request. Soon after, Patrick and Robin's marriage hit a rocky point after Patrick confessed that he and Lisa had a one-night stand while Robin was out of town. As the Chief of Staff, Steve struggled to keep the personal drama out of the hospital and set his personal feelings aside as the tensions rose between Lisa and Robin.

Robin and Lisa argued publically several times at the hospital and each made various accusations against the other. Steve had to intervene often and he frequently had to side with Lisa because Robin appeared less stable. Privately, Steve reassured Robin that he believed in her but his position required him to look at the facts. However, as the accusations between the women continued, Steve started to question if Robin was the one that was unstable instead of Lisa.

Steve took a brief break from his duties overseeing the hospital to chaperone a youth ski trip. His nephew Cameron and several other children and teens attended. Olivia Falconeri was also a chaperone and Steve looked forward to spending some time with her. Instead Steve ended up caring for Olivia and several others who were injured when the bus crashed. In the days that followed, Steve kept a close watch over Olivia as she recovered in the hospital. After she was released, they started dating.

A few months into Steve's relationship with Olivia, he leaned on her for emotional support after his nephew Jake was killed in a nit-and-run accident. Steve remained strong for his sister and helped her out with her other two sons as much as possible. Steve used work as a distraction until Olivia reminded him there was more to life than his grief over Jake. They took their relationship to the next level and became lovers.

Things at the hospital started to settle down when Lisa was taken into police custody after she made an attempt on Robin's life. Lisa escaped and sneaked back into the hospital long enough to take Steve, Patrick, Robin, and Robin's cousin Maxie Jones hostage. Lisa held her own version of a trial in which she played judge and jury as she listed the crimes each of them had committed against her. She accused Steve of questioning her medical capabilities and said he only kept her on staff out of fear she would sue if he fired her. Eventually the group was rescued and Lisa fell into a coma after she injected herself with a syringe of drain cleaner.

Against Steve's advice, Elizabeth came back to work after the death of her son. Steve believed it was too soon but he agreed after she claimed it would help her with her grief. Elizabeth made a potentially fatal error in the operating room and she was temporarily placed on suspension. Steve had to meet with the hospital board regarding the incident and he voluntarily gave up his position as Chief of Staff and recommended Robin as his replacement.

While Robin adjusted to her new position at the hospital, Steve had more time to spend with Olivia. He invited her to be his guest on a private boat cruise Patrick had chartered to celebrate Robin's birthday and the cancer research Patrick's brother Matt had done. Olivia and Steve found some time for romance before they learned that Lisa had emerged from her coma and made her way onto the boat. She went after Patrick and Robin but had disappeared by the time the police arrived. Her dead body washed ashore a few days later an a autopsy revealed she had been murdered. All of the guests on the boat were considered suspects.

The police investigated Lisa's death and Steve was questioned several times about what had occurred on the boat. In the midst of the investigation, Steve's ex-girlfriend from Memphis, Maggie Wurth, arrived in town. Maggie and Steve had worked together at a hospital in Memphis and Steve had recruited her to work as a pediatrician at General Hospital while he was still Chief of Staff. Olivia was not pleased by Maggie's arrival, especially after Maggie repeatedly flirted with Steve in front of her. Steve assured Olivia he was committed to her although Maggie pressured him to remember their time in Memphis and what they had done.

Olivia's ex-boyfriend Johnny Zacchara discovered that Maggie and Steve had a past connection in Memphis that went beyond a personal or professional relationship. Johnny held the knowledge over Steve and threatened to reveal the secret unless he did a few medical favors for Johnny. Steve complied but he felt the pressure increasing.

Things eased up a bit for Steve when the First Mate from the boat cruise confessed to killing Lisa. Maggie had several questions for Steve regarding Lisa and she continued to bring up their time in Memphis and pushed for them to go back to what they used to have. Steve made it clear he was with Olivia and warned Maggie that if she was not careful, she could be headed down the same obsessive path Lisa had taken. Maggie scoffed at the comment and told Steve that he needed her because she was the only person that could provide him with redemption for what had happened in Memphis.

Steve decided to come clean with Olivia regarding the secret he and Maggie shared after Maggie told Olivia that she and Steve were lovers again. Steve shocked Olivia by confessing that he had intentionally killed one of his patients in Memphis. He explained that the patient was a prison inmate that had committed several murders. Meanwhile, Maggie had a young patient that was in need of a heart transplant and Steve's patient was a match. Olivia was shocked to learn that Steve had overstepped his role as a physician to determine which life was more valuable. Steve told Olivia the authorities in Memphis had reopened the case and that Johnny also knew the truth. Olivia told Steve she loved him and promised to intervene with Johnny on his behalf.