Derby born right back Harry Ashby began his career with hometown side Derby Athletic in 1895. In July 1896 he joined Second Division club Burton Swifts making his Football League debut at Loughborough in September 1896, being mainly employed at right back in his debut season and thereafter mainly used at left back, and he made 94 appearances for the club over three seasons scoring 7 times, including scoring a hat-trick when deputising at centre forward in a 5-0 win over Barnsley in December 1898. After a spell of nearly two seasons with Southern League club Brighton United, joining them in the 1899 close season, the club experienced financial difficulties, released their players and were dissolved. Ashby returned to Burton to play for Second Division club Burton United in November 1901, an amalgamation of the Swifts and Burton Wanderers.
Ashby played 105 times for Burton United over the following two years and was an ever present in their 1902-03 and 1903-04 campaigns before moving to Southern League Plymouth Argyle in the 1904 close season. During his only season with Argyle he was virtually ever present at right back and the 1904-05 club handbook describes him as “a player who has had a good reputation among second leaguers for several seasons”. At the end of the campaign he moved on to Leicester Fosse in July 1905 after 41 appearances for The Pilgrims, where he played for two more seasons, playing 68 matches for The Fossils, missing only one match in their 1905-06 campaign, before ending his playing career in 1907.