Born in Aberdeen, Aiken was a painter in oils and watercolours as well as an etcher and stained-glass artist. After serving a six years apprenticeship as a draughtsman with the lithographer Robert Gibb, he studied at Gray's School of Art in Aberdeen and at the Royal College of Art, under Gerald Moira, as well as in Florence. He became Head of Gray's School of Art in 1911-14 before devoting himself full-time to painting full time. He was awarded the silver medal at the Paris Salon in 1923 for his portrait of Harry Townend, previously exhibited at the RA in 1921 and shown again at the Salon of 1929. He lived for a time in London before returning to Aberdeenshire.
Although his earlier work showed the great influence of Moira's decorative technique he gradually developed his own distinctive style. After the death of his wife he settled in Abyme, Aberdeenshire.
His work is represented in Aberdeen, Dundee, and Perth Art Galleries as well as in Leith Hall (National Trust for Scotland).