Jeremy Manning kicked five penalties and a drop goal as he steered Cork Constitution to their first AIB League Division One title since 1999.
The New Zealand-born out-half decided a cagey final at Musgrave Park, with champions Garryowen losing for the first time in 12 games.
Garryowen full-back Conor Kilroy landed a third-minute penalty but three Manning strikes gave Con a 9-3 interval lead.
The table toppers, who had hooker Des Murray sin-binned, moved 18-3 ahead before Garryowen's Lorcan Bourke touched down in the 74th-minute.
CORK CONSTITUTION: Richie Lane; John Kelly, Tom Gleeson, Evan Ryan, Cronan Healy; Jeremy Manning, John Stringer; Daragh Hurley, Des Murray, Tim Ryan, Merle O'Connell (capt), Shane O’Connor, Frank Cogan, Brendan Cuttriss, Billy Holland.
Replacements used: Daragh Lyons for Kelly, Ed Leamy for Cogan (both 65 mins), Robert Quinn for Cuttriss (76), Colum Murphy for T Ryan, David O'Leary for Stringer (both 79).
GARRYOWEN: Conor Kilroy; Cillian O'Boyle, Kieran Lewis, Conan Doyle, Keith Earls; Willie Staunton, Gerry Hurley; Rory Brosnan, Damien Varley, Eugene McGovern, Mark Melbourne, Frank McKenna, Peter Neville (capt), Anthony Kavanagh, Peter Malone.
Replacements used: David Sherry for McKenna (56 mins), Declan Lavery for Brosnan (64), Alan Kingsley for Kilroy (65), Barry O'Mahony for Kavanagh , Federico Quaglia for Staunton (both 68).
AIB man of the match: Jeremy Manning (Cork Constitution)
Referee: George Clancy (IRFU)
