Cefn-y-Bedd, Flintshire born winger Len Williams began his football career with Macclesfield Town, where he was given an opportunity at senior level in two matches including the FA Cup First Qualifying Round away win at Flint, and Spennymoor United in 1928 and joined Third Division (South) Bournemouth & Boscombe Athletic in 1929, making his Football League debut against Southend United in January 1930. After two seasons as a fringe player he broke into the first team on a regular basis in August 1931 and had two full seasons before a move to First Division Portsmouth in the summer of 1933 after 18 goals in 96 appearances for The Cherries.
He played only once in the top flight for Pompey in a 0-0 draw at Tottenham Hotspur in February 1934, before joining Aldershot that summer, where he joint top scored for the club in 1935-36 with 13 goals. He was then signed by First Division Charlton Athletic after 21 goals in 71 appearances for The Shots, where he was again a fringe player making only 3 appearances during his two season stay at The Valley, before returning to Aldershot in the summer of 1938 for a further season, adding a goal in 14 matches to his previous tally. He joined non league Worcester City in the 1939 close season and the outbreak of the Second World War effectively ended his career.