In 1990–91, County achieved promotion from the Fourth Division as runners-up. In 1992 he made his first trip to Wembley Stadium, as Stockport lost 1–0 to Stoke City in the League Trophy final. During the same season, Stockport also reached the Third Division play-off Final, but were defeated at Wembley. The following year, County again reached the League Trophy Final, but lost 2–1 to Port Vale. In January 1994 Gannon joined Notts County on a brief loan spell to help him overcome some personal problems. Returning to Stockport, he finished the season with his fourth trip to Wembley in two years, as County were denied promotion from the Second Division by a 2–1 defeat to Burnley. The team finally achieved promotion from the division in 1996–97 as runners-up. This promotion was built on a strong defence, of which Gannon and fellow centre-back Sean Connelly were a major part. The following season, County achieved an eighth-place finish in the First Division. He played under the management of Danny Bergara, Dave Jones, Gary Megson, and Andy Kilner.