Gavin Johnson started his career with Ipswich Town, making his debut in a 2–0 win over Barnsley on 21 February 1989. He also scored the first ever Premier League goal for Ipswich against Aston Villa on the first day of the inaugural Premier League season in 1992/93.

He moved on to Luton Town in 1995 and then was sold to Wigan Athletic in the same year. After three years at Wigan, he spent a season in Scotland with Dunfermline Athletic, before returning to East Anglia to join Colchester United in 1999 going on to make over 140 appearances. Gavin then had a brief spell with Boston United, before spending a season with Northampton Town and then Oxford United.