Sunderland, County Durham born wing half (he played on both sides) Harry Dreyer began his senior football career with South Shields in 1914, helping them to win the North Eastern League Championship in 1914-15, but his career was soon interrupted by the onset of the First World War which forced the suspension of peacetime football in May 1915. After the War he returned to Horsley Hill, and with South Shields now promoted to the Second Division, Dreyer scored on his Football League debut in a 2-0 win over Clapton Orient in October 1919.
Mainly used at right half, he was a regular in Shields’ first two post war seasons, scoring twice in 60 appearances before a move to newly promoted Crystal Palace in May 1921. Dreyer enjoyed two seasons at Selhurst Park, mainly employed at left half, as Palace consolidated their Second Division status, scoring twice in 58 appearances for them before signing for Third Division (South) club Southend United in June 1923.
Again a regular, he had a single season at The Kursaal, making 27 appearances, but moved to Midland League club Boston Town in 1924, finally moving back to the north east to play for Seaham Harbour in 1925, his last known club before his eventual retirement.