Allan Mathieson was born in Belfast, Northern Ireland, on November 6, 1897. He first made his mark in soccer while serving with the Royal Irish Rifles.
While being a soldier Allan joined Irish League club Glentoran in 1918. He played in 16 league games and scored 5 goals during the 1918-19 Irish League season. After playing in three league games at the start of the 1919-1920 season he went with his regiment to England in September 1919. Allan helped the Royal Irish Rifles win the 1919-1920 Isle of Wight League championship.
In September 1919 Allan signed for Luton Town. He was a very gifted player and the Luton News and Bedfordshire Chronicle later wrote that he was player “who could juggle on a dinner plate”. The Football Association suspended him for two month for misconduct in a match against Southampton on Christmas Day 1920.
Allan could play in both inside forward positions but was mostly used as an inside left. In 1921 he was picked twice for the Irish international team. In April 1921 he played against Wales and in October 1921 he played against England. In the match against England he was one of three Luton forwards picked for the Irish team.
Allan fell out with the leadership of Luton Town during the 1921-22 season and was placed on the transfer list. In March 1922 he was suspended by the club for the rest of the season due to breaking club regulations. After scoring 16 goals in 54 league games he was transferred from Luton to Exeter City on July 1,1922. He was described as probably being the heaviest forward playing professional football.
During the 1922-23 season he set a record when he was ordered of the field twice within a fortnight. Allan was sent off against Merthyr on December 23 and against Reading on January 6. He was suspended for one month by the Football Association for his offenses. He played in 26 league games and scored 4 goals during the 1922-23 season.
The 5’10” and 12 stone forward was signed by New Brighton A.F.C. in August 1923. He was one of five players from Belfast that played for New Brighton in the 1923-24 season. In November 1926 he was joined at the club by his brother John Mathieson. Allan played in 128 league games and scored 37 goals until he was released by the club in May 1927.
Allan then returned to Belfast looking for a new club either in the Irish League or in the Free State League. In July 1927 he was rumored to be on the verge of signing for new Irish League club Coleraine. He helped Coleraine to a sixth place finish in the Irish League in the 1927-28 season.
Allan emigrated to Canada in November 1928. In the immigration records he is listed as being a professional footballer. He joined Ulster United in Canada. In the 1930 season he starred for Ulster United against Scottish touring teams Glasgow Rangers and Kilmarnock.
He returned to Belfast in 1931 and tried to get back into professional football. In November 1931 he signed for Alliance League club Hollywood Rangers. He ended the season spending time in Craigavon Hospital.
Allan served in France during World War II.