John Bewsher was born on May 5, 1894, in Richmond, Surrey, the son of John and Eva Bewsher.

His career started in 1913 when he joined the Sopwith Aviation Co. as a junior draughtsman, and he is one of the few people who can claim to have designed a complete aeroplane by himself from start to finish. At Sopwith he rose to be assistant to the chief designer Herbert Smith and was concerned with all the famous Sopwith types of the First World War, specializing in the design of controls and main structures and in stressing. He worked for the Sopwith firm until it dissolved in October 1920.

In February 1921, the Mitsubishi Internal Combustion Engine Manufacturing Company in Nagoya invited Smith, along with several other former Sopwith engineers including Bewsher, to assist Mitsubishi in creating an aircraft manufacturing division. Smith and his team moved to Japan, where they designed the B1M, 1MF, and 2MR.

Bewsher returned to England in 1924 and joined the Air Navigation and Engineering Co. (A.N.E.C.) as chief engineer on W.S. Shackletons departure to Beardmore in 1924, and was responsible for the ANEC III, a redesign of the Handasyde H.2. The new design first flew at Brooklands on 23 March 1926.

Bewshers next, and last, design for the Air Navigation and Engineering Co was the ANEC IV biplane, designed for the 1926 Lympne light aircraft trial for two seaters fitted with engines of less than 170 lb. It did not make the competition as the undercarriage collapsed in a taxiing accident.

In 1927, he joined Vickers Aviation as senior draughtsman under Pierson, and was successively assistant chief draughtsman, chief draughtsman (experimental), drawing-office manager and design office manager, responsible for administering all the design departments.

While working at Vickers, Bewsher also produced designs for other companies on a freelance basis. He designed the Henderson HSF.1, intended as a four passenger joy-riding aircraft, in 1927, the Surrey Flying Services AL.1, a single-engined side-by-side two-seater in 1929 and in 1931 was responsible for the design of the R.F.D. Sailplane.

He retired from Vickers-Armstrongs (Aircraft) Ltd in February 1959. John Bewsher died in mid-1974, in Worthing, Sussex.