Sims painted portraits, landscapes, and decorative
paintings. He was one of that group of artists who continued to treat symbolic
and romantic themes after the First World War.

He received his art education in London
in the South Kensington and Royal Academy Schools,
and in Paris in
the ateliers of Julian and Baschet. His continental training probably
accounts for his fluent handling of paint, and his confident treatment of space
and atmosphere. These qualities rapidly gained him critical and academic
success. A picture was bought for the Paris
gallery of modern art, the Luxemburg, in 1897 and for the public gallery in Sydney, Australia
in 1902. He held a highly successful one man show at the Leicester Gallery in
1906, and ‘The Fountain‘ was bought for the Chantrey Bequest in 1908.
Academic honours followed. He was elected Associate of the Royal Academy
in 1908, Associate of the Royal Watercolour Society in 1911, Member of the
Royal Watercolour Society in 1914 and Royal Academician in 1915. He became
keeper of the Royal Academy Schools in 1920.

The First World War proved to be a traumatic experience for
Sims, from which he never recovered. His eldest son was killed and he was
unbalanced by what he witnessed in France where he was sent as a war
artist in 1918. His subsequent paintings often show signs of the mental
disturbance which led him to resign his post at the Royal Academy Schools in
1926. In 1928, Sims committed suicide. A study of his life by one of his sons
appeared in 1934, and a selection of his work appeared in the Last Romantics
exhibition (Barbican Art Gallery, London 1989).