Victory for champions Airdrie consigned long-time league leaders Morton to a fourth place finish in Division Two.
The first goal came on 52 minutes when Owen Coyle laid the ball off for Andy Gow to fire home from distance.
The visitors worked hard but rarely threatened and relied on keeper Craig Coyle to keep them in the game.
The dominant Diamonds added to their tally with a minute remaining when Matt Roberts touched the ball inside to Coyle, who scored with a cute lob.
Airdrie Utd: McGeown, William Wilson, Lovering, McGowan, McManus, Dunn, Vareille, Marvyn Wilson, Coyle, Gow, McLaren.
Subs: Scott Wilson, McKeown, Roberts, Glancy, Hollis.
Morton: Coyle, Collins, Henderson, Macgregor, Greacen, Marco Maisano, Millar, Cannie, Weatherson, Hawke, Bottiglieri.
Subs: Walker, Williams, McAlistair, Adam, McGurn.
Referee: W Young