Born in London, Maidment was a student of the Royal College of Art in early years. With talents in draughtsmanship, he won a travelling scholarship.
Living first in Newlyn from before WWI, he worked and remained there until 1932 when he moved to St Ives, joining the St Ives Society of Artists (1932-59). In 1944 he moved to Helston and later to Torquay, in 1952; but he kept his working and exhibiting ties in St Ives.
Maidment is especially noted for his detailed paintings of the many quaint houses and byways of St Ives. He was included in the exhibition to celebrate the Centenary of Cornwall County Council: A Century of Art in Cornwall 1889-1989.