Tustin started working in 1914 at the age of 16 as an apprentice to the C. A. Parsons and Company, of Newcastle upon Tyne.
He entered Armstrong College, later part of Newcastle University, in 1916, served in the Royal Engineers in World War I, and eventually received his master's degree in science in 1922.
In the early 1930s he worked for Metro-Vick in Russia for two years, advising and selling equipment to the government companies.
[2] In the late 1930s and during World War II Tustin was working on the Metadyne constant-current DC generator for gun control.
[3] He also developed new methods for gyroscopic stabilisation and further applied servo-mechanisms to tanks and naval guns.