Hartley joined West Ham United as a junior in 1966. He made his first-team debut in a 3-1 away defeat by West Bromwich Albion, on 28 April 1967. He made only five appearances for West Ham as a right-winger between 1967 and 1969 before being transferred to Bournemouth where he made 42 appearances between 1969 and 1971 scoring two goals.
Between 1974 and 1975 he was manager at Bournemouth. In 1986 he became David Pleat's Assistant Manager at Tottenham and when Pleat stood down in October 1987, he stood in as caretaker manager together with Doug Livermore who subsequently took charge, pending the arrival of Terry Venables in November that year. He later took charge of the national team of Malaysia between 1988 and 1990.