Alfred Forrester was born in Otago in 1895. The Forrester family immigrated from Kings Kettle, Fifeshire, Scotland on the ship Oamaru landing at Port Chalmers in 1879. His father, William Forrester, was a carpenter by trade and the family lived at 13 Percy Street, Weston. The youngest of eight children, Alfred Forrester was educated at Cave School. He married Hazel Isabel Mason of Dunedin in Columba Church, Oamaru 1916. The couple relocated to Dunedin where Forrester received tuition from fellow Scottish artist J C Veitch and W A Bollard. Forrester continued his training under A H O'Keefe in Christchurch. In 1920 he attended the Christchurch School of Art under Cecil F Kelly, and help found the North Otago Art Society that same year.

Forrester returned to Oamaru, establishing a studio where he taught 'landscape, flower and fruit painting' to his students. He was also a regular exhibitor with the Otago Art Society. Forrester is buried in the Oamaru Cemetery.