St Helens, Lancashire born inside forward Arthur Mercer played junior football for Parr St Peter’s in 1920 before joining Wigan Borough in 1921, making his Football League debut at Barrow in April 1922. Initially mainly a fringe player, he established himself in Borough’s first team from October 1924, and his 11 goals during 1924-25 attracted First Division Bury to sign him in June 1925 after 16 goals in 40 appearances. He scored 3 goals in 11 appearances for The Shakers before he was signed by Sheffield United in October 1926, joining his older brother David at Bramall Lane. After a successful first season, where he scored 15 goals in 29 games for The Blades, he made only 7 further appearances during 1927-28 before joining non league Rhyl Athletic in 1928, moving to Connah’s Quay & Shotton in 1929.
He returned to Football League action with Bristol City in May 1930, scoring 8 times in 31 appearances for The Robins during 1930-31, but he only featured once more the next season before joining Chester in October 1931. He featured prominently in a competitive Chester team during his two years at Sealand Road, they finished third and fourth in the Third Division (North), and by the time he joined Halifax in November 1933 he had scored 19 times in 70 appearances. He helped Halifax to runners up spot in the Third Division (North) in 1934-35, narrowly missing out on promotion, and left the club in the 1935 close season after 8 goals in 47 appearances, joining non league Dartford, before returning a year later to Rhyl where he finished his career.
He was the younger brother of David Mercer, who played for Hull City, Sheffield United and England.