The biggest impression he made in the majors was at the U.S. Open in 1988, where he was only one stroke off the lead after the first round; he went on to finish in a tie for 50th place.

He played almost exclusively on the PGA Tour through 1994 when he again lost his card by finishing 131st on the money list.

After turning 50 in 2001, Mast started playing on the Senior PGA TOUR and placed eighth in the 2001 qualifying school to earn full exempt status for 2002.

In January 2012, Mast won the Qualifying School for the European Seniors Tour.

[1] *Note: The 1990 Ben Hogan Gulf Coast Classic was shortened to 36 holes due to rain.