Staindrop, County Durham born left back Don Ashman began his football career with Evenwood Juniors and played for Cockfield. Second Division club Middlesbrough paid Cockfield a £10 fee and the promise of a friendly match for Ashman’s services in 1924, and he made his Football League debut at Coventry City that November. Establishing himself in the first team from March 1927, he missed one match as Middlesbrough won the Second Division Championship in 1927, scoring the first of his two career goals in a 4-1 win over Darlington in March 1927.
He appeared less frequently the following season as Middlesbrough failed to maintain their First Division status, scoring his only other goal in a 2-0 win over Blackburn Rovers in September 1927, and played only 3 times in 1928-29 as they again won the Second Division Championship. He played regularly in 1929-30, but after two more years during which he made just 23 appearances, he moved to Queens Park Rangers for a £500 fee after 174 appearances for Middlesbrough.
Ashman appeared intermittently during his first season with The R’s, but in 1933-34 he was ever-present in the left back position in Third Division (South) matches, and having played in about half of the following season’s fixtures he was transfer-listed in 1935. In July, he was granted a free transfer after 87 matches for Rangers, and amid interest from York City and other clubs, signed for Third Division (North) club Darlington. After playing in the first 15 matches of the season, Ashman sustained an injury and was replaced at left back by Charles Allan, who kept his place to the end of the season. Ashman was released on a free transfer, and retired from football.