He was married to acclaimed Streatham-born artist Winnifred Knights of Madeira Road
Monnington was the son of a barrister and although he was born in Westminster, London, he grew up in Sussex before spending time on a farm school at Ross-on-Wye.
From 1918 to 1922, he studied at the Slade School of Fine Art and in 1922 won a three-year scholarship to the British School in Rome.
In April 1924 Monnington married his fellow art student and and acclaimed artist Winifred Knights. Whilst in Italy, he produced his first large work, Allegory which was purchased by the Contemporary Art Society and is now in the Tate collection
Image of Monnington by Godfrey Argent ©National Portrait Gallery