Bentworth, Hampshire born outside left Harry Osman played junior football for Okeford United, before joining Poole Town, playing in the Western League, in 1930. In December 1935, having caught the eye of several clubs, he joined Second Division Plymouth Argyle making his Football League debut at Bradford Park Avenue in April 1936. Despite making only five appearances for Plymouth, he had previously impressed Tom Parker when he was manager of Norwich City. On joining Southampton in 1937, Parker signed Osman from Plymouth that June on a free transfer, making his debut for Southampton in the Second Division on 28th August 1937, the first day of the 1937-38 season. Osman made an immediate impact, scoring in a 3-4 defeat by Parker’s old club at Carrow Road.
His next goal came on 18 September (against West Ham United) before starting a run of form in October which saw him score eight goals in four games, including a hat-trick in a 3-6 defeat at Luton Town. On Christmas Day 1937, The Saints played a home league match against Swansea Town in which Osman scored to bring the result level at 1-1; this was the last goal scored at The Dell on a Christmas Day. Although Christmas Day fixtures continued on and off until 1959, all the Saints’ subsequent Christmas Day matches were away from home.
Osman’s form continued and he only missed two matches at the end of the season, when he was The Saints’ top scorer with 22 goals (a club record for an outside left) from 41 appearances. His form had attracted the attention of bigger clubs, but a reported bid of £7,000 from Birmingham failed to materialise. The following season, Osman continued to play well in an unsettled Southampton side that struggled to maintain any form. Unable to find the exciting form of the previous season, Osman managed only nine goals from 30 appearances before he was sold to Second Division rivals Millwall in March 1939 for a fee of £2,000, a move that came as a shock to the Southampton fans, although, in hindsight, this turned out to be a very good piece of business.
His career at Millwall was interrupted by the Second World War, by when he had made only 10 appearances for The Lions. He returned to The Dell as a guest player in War Leagues in 1939-40, before joining the Tank Corps where he was wounded while serving in Italy. After the War, he returned to Millwall scoring 3 goals in 27 appearances before transferring to Bristol City in October 1947, where he scored once in 21 appearances over the remainder of the season. At the end of the 1947-48 season he dropped down to non league football with spells at Dartford and then Canterbury City where he was appointed player-manager in 1951, staying a season.
Having joined Winchester City as a player in 1952, and after a few first team appearances, he was appointed manager in 1953 where he discovered future England international Terry Paine before leaving in 1957.