Doyle was born in Woonsocket, Rhode Island and raised in the Boston suburb of Norwood, Massachusetts. He attended Catholic Memorial High School in West Roxbury, Massachusetts, and Norwich University in Vermont where he hosts an annual golf tournament to benefit the Norwich Hockey Team. Despite winning numerous amateur titles, he did not turn professional until he was 46. In 1995, his first full professional season, he won three times on the Nike Tour.

From 1996 to 1998 Doyle competed in 58 PGA Tour events, making the cut in 31, including two top-10 finishes.

Doyle became eligible to play on the Senior PGA Tour when he turned 50 in July 1998 and won four official money events in 1999, including the Senior PGA Championship. In 2001 he won his second senior major, the Senior Players Championship, and led the tour on the money list. In 2005 he claimed a third major at the U.S. Senior Open, coming behind from a nine stroke deficit with a 63 in the final round. He successfully defended his U.S. Senior Open title in 2006 by defeating Tom Watson at Prairie Dunes Country Club and becoming the oldest U.S. Senior Open Champion at 57 years, 11 months and 17 days. His career earnings on the Champions Tour at the time of his retirement is listed as $13,401,250.