R. J. Mitchell was born in the village of Talke, Stoke-on-Trent, in England. After leaving Hanley High School at the age of 16 he gained an apprenticeship at Kerr Stewart & Co. of Fenton, a locomotive engineering works. At the end of his apprenticeship he worked in the drawing office at Kerr Stewart and studied engineering and mathematics at Night School. In 1917 he joined the Supermarine Aviation Works at Southampton and in 1918 was appointed Chief Designer at Supermarine.
Between 1922 and 1931 he designed seaplanes including the Supermarine S6B which won the Schneider Trophy in 1931 and the Supermarine Walrus.
The S6B prompted the Air Ministry to invite Mitchell to tender for the design of a new fighter aircraft designated the F7/30 and on the 20th February, 1932 Mitchell submitted his Type 224 design. In 1933 he was authorised to proceed with the design of this all-metal monoplane that would become the Supermarine Spitfire.
Late in 1933 Mitchell underwent surgery to treat abdominal cancer and as part of his convalesence went on holiday to Germany in 1934. The effect of this visit to Germany was to convince him of the importance of the Spitfire in the face of Nazism and German re-armament. He worked feverishly on not only the Spitfire but also a four-engined bomber, the Type 317.
The first iteration of the Spitfire design, the Type 224, first flew on the 19th February 1934. Mitchell referred to it as "The Shrew". Its performance was unsatisfactory and he began work on the Type 300 that would become the Spitfire. The first prototype Spitfire, K5054, flew for the first time on the 5th March, 1936 at Eastleigh.
Mitchell died of cancer in 1937 after returning from a short stay at the American Foundation in Vienna. His life, and the sacrifices he made to keep going despite pain and impending death, was the subject of the 1942 Leslie Howard movie "The First Of The Few", which although inaccurate in places served to show the importance of his work years after his death.