Peter was born to Palmer and Opal Cortlandt on Christmas Eve in 1992. Opal, who thought she had entered menopause, was surprised to learn that she was pregnant. Palmer was equally surprised to learn of Opal's pregnancy because he thought that a riding accident many years earlier had left him sterile. A DNA test finally proved to Palmer that Opal hadn't been unfaithful, and that Peter was his son.
A growing Peter Cortlandt proved to be a handful for most of his nannies, one of whom was Kendall. He was ultimately sent away to boarding school.
Peter returned to Pine Valley on July 11, 2008, and began to socialize with his childhood friend, Colby Chandler. He soon realized that he was falling in love with Colby, but she did not return his feelings. In the meantime, Peter entered into a deal with the devil when he hatched a plan with Adam Chandler to taint Fusion's new perfume, Bella, with a chemical that would cause an allergic reaction in anyone who came into contact with it. Negative press coverage about the sabotaged perfume was meant to devalue Fusion's stock, making the company more vulnerable to being seized by Adam.
Peter put his plans to attend Harvard temporarily on hold while he worked at Fusion. At every opportunity, Peter continued his attempts to gain Colby's attention and affection. He eventually succeeded in getting Colby to spend time with him, but their friendship never truly developed into anything more.
In late 2009, Opal revealed that Peter has left Pine Valley and was living in Switzerland, where he'd become enamored by a Swiss "snow bunny."
In 2013, Peter returned to Pine Valley using the name Pete. He planned to visit his mother as part of his brief trip and ignored her suggestion that he remain in town and resurrect Cortlandt Electronics. However, he extended his stay after he met a young woman named Celia Fitzgerald. Although Pete was a worldly entrepreneur, he was drawn to Celia despite her innocence and strict guardian Evelyn. When Evelyn tried to end Celia's relationship with Pete, the couple escaped to New York and spent a chaste night together in a hotel room. Soon after their return Celia ended their relationship.
Pete did not understand Celia's decision but soon had his hands full with his new business partner David Hayward. David unexpectedly ambushed Pete by making a substantial investment into Cortlandt Electronics and forced the partnership on him. Meanwhile, Pete's high school crush Colby Chandler returned to Pine Valley and was impressed with how Pete had grown up. They spent the night together and afterwards Colby hoped that it was the beginning of more. Pete explained that he was only interested in being friends with benefits. However, Pete declined the repeated offers for benefits from Colby and hoped to reconcile with Celia.
Celia and Colby worked together to plan a charity event hosted by Chandler Media. The event included a bachelor auction and Pete agreed to participate as an excuse to talk to Celia. On the night of the auction, an anonymous caller placed a bid on Celia's behalf and she won the date with Pete. He recalled Celia's favorite romantic movie scene and recreated it for her. Their date was interrupted after Celia was sprayed by a skunk but the incident brought them closer.