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.