Jimmy Formica's rival, Frank Holloway's arch enemy.
Madigan gives the impression of being an legitimate business man. But under the surface he's involved in drug dealing, extortion, and even murder. Frank has sworn to get him.

Season 3 (1998)
Episode 62 (59)"Old dog, old tricks"
Episode 71 (63)("Let the dead"
Episode 75 "Untouchable"
Episode 79 "Honour amongst thieves"
Episode 80 "Trust"
Episode 81 "War games"
Episode 82 "Last impressions"