Gary is Father of Robbie Jackson and Kevin Bolton who lived with his mother Carol Jackson as her boyfriend, and her daughter Bianca until a year after Robbie's birth. When David Wicks is revealed as Bianca's father in 1994, Carol tells Robbie she had left his father because he was having relationships with under-age girls; however, this is retconned when the character appears on-screen for the first time in 2001. He tries to get in touch with Robbie on his eighteenth birthday by phoning Carol's father Jim Branning but Jim refuses to give Gary Carol's number.
In May 2001, Robbie and his half sister Sonia go to Portsmouth to find Gary. They find his number when they see an advert for a builder called G. Bolton. When they go to his house, Gary gives Robbie a present he has saved from his first birthday and a cheque to make up for "backdated pocket money". Robbie then meets his half brother, Gary's son Kevin Bolton, and when he realises that Gary had left Carol to be with Kevin's mother, he throws the cheque back at Gary and leaves. In June, Gary arrives in Walford to talk to Robbie. He tells Robbie he will pay for him to go to college, but Jim tells him to leave. Later, in July, Gary returns to Walford and is happy to see old friend Mo Harris. Gary and Mo spend the day reminiscing in The Queen Victoria pub, and when Robbie comes in, Gary gives him a cheque for £10,000. This is the last time Gary is seen. Robbie uses £1,000 of his money to travel to India, and gives Sonia £9,000 to pay her college fees.