Born at Stocking Pelham, Hertfordshire, he studied at Royal College of Art, South Kensington, and at Westminster School of Art under Brown.
Hartley moved to St Ives with his wife, the artist Leonora LOCKING (aka Nora), in 1904, living consecutively at two addresses on Bellair Terrace. They joined the St Ives Arts Club in 1906. During his time in St Ives, Hartley was known as a master in etching and coloured aquatint, and went on to develop an international reputation for print work.
In 1907 he exhibited and sold the etching An Essex Stream at NAG. He also founded the New Print Society in St Ives, and in 1911, 1913 and 1924 exhibited at St Ives Show Days. In 1924, both he and his wife showed work from their travels to Bordighera, Italy, Alfred showing charming small pastel studies, Nora painting the streets and the town. He was a master at evocative atmospheric effects, though in his later years he became crippled with arthritis.