Maciej Zurawski gave Celtic a half-time advantage and Shaun Maloney put the game beyond doubt when he scored with a 20-yard free-kick after 76 minutes. Substitute Dion Dublin added a third in injury-time.
In a final what was billed as a tribute to Celtic legend Jimmy Johnstone who died last week, it was fitting that the current number seven should score the opening goal.
But the final was not the best spectacle as Dunfermline seemed content to sit back and frustrate Celtic.
It was one-way traffic from the kick-off. Celtic spent almost the entire opening 45 minutes in the Dunfermline half but did not create too many clear-cut chances.
An early corner from Shunsuke Nakamura came off Maloney's head and also the head of a Dunfermline defender before hitting the face of the bar.
But, apart from that, the Pars seemed to cope with most of what Celtic could muster as they defended in depth and denied the SPL leaders any space.
Allan McGregor was well positioned to hold a free-kick from Nakamura and Ross Wallace thumped a 20-yard shot wide.
Dunfermline's only chance came after Wallace and Stephen McManus were involved in a defensive mix-up to give Freddy Daquin an opening, but the angle was too tight and he rushed his shot into the side-netting.
McGregor produced his best save to keep out a Roy Keane header after 39 minutes from a Nakamura free-kick.
But Celtic were gifted the breakthrough three minutes from half-time. McGregor collided with Aaron Labonte as he came out of his goal and the ball broke to Zurawski who rolled it in from a tight angle.
McGregor saved well again from Zurawski seven minutes into the second half after Maloney had set up the striker.
Celtic lost Keane with a hamstring injury after 61 minutes and Dublin took his place.
The substitute missed an open goal moments later when he slipped the ball wide from just six yards after great work from Maloney.
Maloney capped a fine individual performance when he curled home the second goal direct from a free-kick with 14 minutes left.
Dublin made it 3-0 when he slipped the ball home from six yards from a Paul Telfer cross in the dying seconds.