The 60-year-old Morgan won at Pebble Beach 15 years after a disappointing finish in the U.S. Open on the historic course. In 1992, Morgan was 12 under after seven holes of the third round, the lowest anyone had been in a U.S. Open, but played the next seven holes in 9 over and ended up tying for 13th.
'Pebble Beach is finally going to let me survive,' Morgan said. 'I kept thinking, 'It's going to give me a reprieve.''
Morgan finished with a 14-under 202 total, birdieing four of the first six holes Sunday and adding another on No. 16. He opened with a 70 at Pebble Beach and shot a 65 on Saturday at Del Monte.
'I was able salvage some par putts and I think that was the difference today,' Morgan said.
The 62-year-old Irwin closed with a 69. Irwin who began the round tied for the lead with Morgan and Smyth, opened with a double bogey and missed a 3 1/2 -foot birdie put on the 15th hole.
'It's a long way to come back. You just can't come back from double bogeys, particularly when it's right out of the box,' Irwin said. 'It was such a reverse momentum, I knew I was in a big, big hole.'
With the victory, Morgan broke a tie with Miller Barber for third place on the 50-and-over tour's career list. Irwin is the leader with 45, and Lee Trevino has 29 wins.
Tom Watson shot a 69 to finish third at 10 under. Scott Simpson, the 2006 winner, had a 67 to join Des Smyth (73) and Don Pooley (67) at 8 under. Bernhard Langer shot a 71 to tie for 10th at 6 under in his Champions Tour debut.
Morgan earned $300,000 from the $2 million purse.