County manager Gannon, the former Shelbourne player and Dundalk manager, had been a Wembley loser four times with Stockport, but saw them clinch their first promotion in 11 years yesterday.
The Hatters fell behind to Rochdale defender Rory McArdle’s 23rd-minute corner, but once Nathan Stanton’s own goal hauled Stockport level, Gannon’s side seized control.
Anthony Pilkington headed County into a 49th-minute lead and Liam Dickinson bludgeoned home a third before Dale winger Adam Rundle set up a nerve-jangling finale with a 77th-minute volley.
Gannon lifted County from the depths of League Two in January 2006 and this win will ease the memory of two Wembley play-off final losses and two defeats in the final of the Autoglass Trophy.
Rochdale’s defeat in their first Wembley appearance consigned them to a 35th successive year in the fourth tier of English football.
Logan, Rose, Owen, McNulty, James Smith, Dicker, Gleeson (McSweeney 75), Rowe, Turnbull, Pilkington, Dickinson (McNeil 90).
Lee, Ramsden, Kennedy, Stanton, McArdle, Rundle, Jones, D’Laryea (William Buckley 73), Dagnall, Le Fondre (Howe 57), Higginbotham (Muirhead 46).