Hanley, Staffordshire born outside right Jack Mandley began his football career playing with Cross Street Mission and Boothen Vics before he joined local professional club Port Vale as an amateur in August 1926 signing as a professional in May 1928 and making his Football League debut at Hull City the following September. He scored his first senior goal on 13th October 1928, in a 3-2 win over Preston North End at The Old Recreation Ground, and also scored in a 2-1 home defeat to Potteries derby rivals Stoke City on 26th January 1929, finishing the 1928-29 season with five goals in 36 appearances.
He then suffered a spell on the sidelines between May and December 1929 due to injury, and after one goal in 15 games in 1929-30 he was sold to Aston Villa for a £5,000 fee in March 1930, despite great protests from the Vale supporters. Vale went on to finish the season as Champions of the Third Division (North).
The Villains finished fourth in 1929-30, with Mandley scoring once in eleven appearances. He scored eight times in 34 games in 1930-31, as Villa finished as runners-up in the League Championship, seven points behind champions Arsenal, and after a 5th place finish in 1931-32, he scored six goals in 33 appearances as Villa again finished second to the same opponents in 1932-33, this time four points behind Arsenal. However, he was limited to two goals in six appearances as Villa finished 13th in 1933-34. He had spent just over four years at Villa Park, scoring 26 goals in 112 appearances.
In August 1934, still only 25, he left the top echelons of professional football and moved to non league Altrincham, who were then playing in the Cheshire County League, and he subsequently finished his career with them.