Harold Blackmore was born in Silverton on 13th May 1904. After playing local football he joined Exeter City in 1924. A centre-forward, he scored 45 goals in 71 games for the club.
In April 1927, Charles Foweraker, the Bolton Wanderers manager, paid £2,150 for Blackmore. He was a replacement for Joe Smith who had just been sold to Stockport County. Blackmore joined a team that included David Jack, Jimmy Seddon, John Reid Smith, Billy Butler, Ted Vizard, Dick Pym and Alex Finney.
Blackmore scored on his league debut against Sheffield Wednesday. The following season he scored 8 goals in 12 games but it was not until the 1928-29 season that he won a regular place in the first-team. He ended up that year as the club's leading scorer with 37 goals in 43 cup and league games. This included hat-tricks against Portsmouth, Aston Villa and Birmingham City.
Blackmore was Bolton Wanderers top goalscorer in the 1929-30 season with 30 goals. He repeated the feat the following season. This included scoring in seven consecutive games. Blackmore had scored 111 goals in 153 games for Bolton by the time he left the club in 1932. He also had a good goalscoring record at Middlesbrough (9 in 19), Bradford Park Avenue (32 in 60) and Bury (4 in 8).
Harold Blackmore died in 1989.