Maesteg, Glamorgan born right back Emlyn Williams began his senior football career with Wrexham, being on their books in 1934-35 without making a first team appearance. He joined Burton Town in 1935 before signing for Second Division Barnsley in October 1936, making his Football League debut at Bradford Park Avenue in January 1937, and he was a regular in the Barnsley first eleven in the final two seasons before the Second World War, missing only one game in 1938-39 when The Tykes, having suffered relegation in 1938, immediately regained their Second Division status by winning the Third Division (North) Championship.
In June 1939 he was signed by First Division Preston North End after 93 appearances for Barnsley, and he played in their opening three fixtures of the 1939-40 season which was abandoned in September 1939 after the outbreak of the War. During the War he guested for Stoke City and when the conflict was over he returned to Deepdale playing regularly in the first two post war League seasons, helping them to seventh place League finishes both seasons, before a return to Barnsley in April 1948 after 78 appearances for The Lilywhites. He had half a season at Barnsley making 17 further appearances before joining Accrington Stanley in December 1948, for whom he played a further 15 games before retiring in 1949.