Festing was born in 1941 he educated at Ampleforth College and RMA Sandhurst. He was commissioned into The Rifle Brigade where he served until 1969.
Festing worked at Sotheby’s in 1969 and was head of the British Pictures Department from 1977-1981, where he became Sotheby’s chief expert for British Pictures, with and extensive knowledge of portrait painting over the last 400 years. He painted many portraits whilst in the army and at Sotheby’s, and took up fulltime portrait painting in 1981.
Festing became a member of the Royal Society of Portrait Painters (RP) in 1989 and was President from 2002-2008. He was awarded a MBE in 2007 for services to the arts, and holds an Honorary Degree from Northumbria University (2010).