Garry comes to Walford, along with his girlfriend Lynne Slater and her family. Thinking himself a big hit with the ladies, Garry flirts with numerous women and is unwilling to settle down. Eventually he and Lynne get engaged and, on 7 December 2001, marry despite Beppe di Marco trying to stop the wedding. Beppe declares his love for Lynne but she marries Garry.
He finds work as a mechanic and lives with the Slaters. However, Lynne has an affair with her ex-fiancé, Jason James. The couple pull through and decide to try for a baby. In November 2002, Garry has a drunken one-night stand with Laura Beale and is stunned on Christmas Day when she tells him that she is expecting his baby. Her husband Ian throws her out, assuming she has been unfaithful so Lynne takes pity on Laura and allows her to stay, much to Garry's horror, until Ian tells her that Garry is the father of Laura's baby. Lynne is distraught but eventually forgives Garry. However, the couple separate in July 2003 after Garry misses a date with Lynne to support Laura during labour. After being thrown out by the Slaters, Garry and Laura lived together, naming their son, Bobby Beale, in honour of Garry's favourite footballer Bobby Moore. When Bobby needed a blood transfusion, Laura discovered that Ian was in fact Bobby's father as Garry's blood group was incompatible. On returning from hospital, Laura tried to get Ian interested in Bobby but when he refused to have anything to do with her or baby Bobby, she kept quiet about Bobby's paternity because she wanted him to have a father.
Garry and Laura's relationship didn't last as he was still in love with Lynne and they eventually reconciled after Garry had a fling with Lynne's sister, Belinda Peacock, in November 2003, making Lynne realise that she still loved Garry. Lynne later became pregnant with his child. After Laura's death on 30 April 2004, Bobby moved in with Garry and Lynne. Lynne struggled to accept him but was relieved when Pat Evans revealed that Ian was Bobby's father after finding Bobby's birth certificate. Garry was persuaded to give Bobby to Ian, devastating him; further upset occurred when Lynne, unconscious after a fairground accident, needed an emergency caesarean. Lynne survived but their daughter, Vivienne, was stillborn. Unable to forgive Garry for allowing the operation, she left Walford after Vivienne's funeral. Devastated, Garry tried to commit suicide but was saved by Minty Peterson. Garry moves in with Minty and they become good friends, surviving Garry's dislike of Minty's girlfriends...and Minty's brief engagement to Hazel Hobbs - Garry's mother.
Garry becomes infatuated with Dawn Swann, but his attempts to make her notice him are rebuffed. Dawn dates other men and uses Garry's generosity on various occasions. Garry supports Dawn after the death of her fiancé, Jase Dyer, and believing she has romantic feelings for him, proposes. When Dawn refuses, he storms off, terrifying the locals when his car is found at a popular suicide spot. Fearing Garry has killed himself, Dawn realises her true feelings for him and tells a crowded Queen Vic that she loves him, only for Garry to enter and overhear. Despite her initial shock, Dawn and Garry begin dating, eventually becoming engaged but in July 2009, Dawn has an affair with Garry's boss, Phil Mitchell. Minty finds out and tells Garry, who punches Phil and decides to leave Walford on his and Dawn's wedding day. He goes to a canal and boards the boat he and Minty have been keeping and as he is sailing away, Dawn arrives and runs alongside, telling him how much she loves him. He docks the boat, letting Dawn and her daughter, Summer, onboard and they sail away together.
On 21 September 2010, Minty rings Garry due to him leaving Heather and asks if he can come and live with them for a while, thinking that its time to move on.