Harold Holt joined Exeter City from Bolton Wanderers and played in the Southern League for the club between 1913 and 1915. A member of the team which toured Argentina and Brazil in 1914, he later guested for Manchester United after the suspension of official football in 1915.

Starting at Lever Bridge Amateurs, Harold had an unsuccessful trial with Bolton Wanderers in 1908 before moving on to play for Lever Bridge Amateurs, Atherton and Little Lever Lads Club. Trying his luck in the professional game again he failed to secure a contract with Norwich City before, after eighteen months with Walkden Central, finally getting his chance with Bolton Wanderers in February 1913.

His time at Burnden Park was to be short-lived as he was soon on the move to Exeter City. Arriving at St James’ Park aged twenty-two, Harold made his Grecians debut in a Southern League fixture at Gillingham on 18 October 1913. After that he never looked back and was a virtual ever-present for the rest of the season as he scored three goals from 30 league starts.

A highlight of that first season was Harry scoring twice in the 4-0 FA Cup win at Portsmouth in January 1914. Regarded as City's most eye-catching performance in professional football up until then, it earned the Grecians the right to face Aston Villa at home in the following round. With 9,500 present at St James' Park on 31 January 1914, Harry was part of the team that suffered a 2-1 loss to the First Division 'giants' who went on to reach the semi-finals and finish runners-up in the league.  

Touring Argentina and Brazil in 1914 he appeared against Brazil in Rio before appearing in all 38 league games during 1914/15 when he scored on four occasions.

Heading back to Lancashire on the suspension of football for the duration of the war, Harold made guest appearances for Manchester United, Rochdale and a number of other clubs.