Birmingham born outside left Billy Marshall began his football career with Rotax Works after the First World War and joined Midland League club Chesterfield in 1920. After Chesterfield joined the new Third Division (North) in 1921, Marshall made his Football League debut at Stalybridge Celtic in their inaugural League fixture in August 1921, in which they were humbled 6-0. but he scored his first League goal in the return match a week later, which Chesterfield won 4-0. Marshall was a regular for The Spireites during their first two seasons in the Division, helping them to finish fourth in 1922-23, after which he joined Grimsby Town in July 1923 after 10 goals in 72 appearances for Chesterfield.
At Grimsby Marshall made the outside left berth his own, and was a model of consistency over the next nine seasons. He was an ever present scoring 9 goals as Grimsby won the Third Division (North) Championship in 1925-26, and remained ever present in their first season in the Second Division, helping them to win promotion to the First Division in 1928-29 when they finished Second Division runners up. He then played three seasons in the top flight for The Mariners, missing only one match in 1930-31, before leaving Grimsby Town to join Reading in June 1932 after their relegation at the end of the 1931-32 season, Marshall having scored 62 goals in 363 appearances for Grimsby.
He scored 4 times in 20 appearances for The Royals during a single season at Elm Park, helping Reading finish fourth in the Third Division (South) before leaving them to join non league Boston Town in the summer of 1933, where he played until his eventual retirement.