Simonds was called to the bar in 1906, and appointed a King's Counsel in 1924. He was elected a Bencher of Lincoln's Inn in 1929 and was Treasurer from 1951. He served as a Judge of the Chancery Division of the High Court of Justice between 1937, when he was knighted, and 1944. In the latter year he was appointed a Lord of Appeal in Ordinary, sworn of the Privy Council and created a life peer as Baron Simonds, of Sparsholt in the County of Southampton.