Kerensky was born in St. Petersburg, Russia, the son of future Russian prime minister Alexander Kerensky, who survived the events of the Russian Civil War and emigrated to Paris in 1918. Both Oleg and his younger brother Gleb graduated as engineers in 1927, and both settled in England.
As an associate of Dorman Long, Kerensky assisted on the landmark 1932 Sydney Harbour Bridge. As an associate, and then a partner, in the firm Freeman Fox & Partners, Kerensky designed many British road bridges and structures such as the 1951 temporary Dome of Discovery in London, the largest dome in the world. He was president of the Institution of Structural Engineers in 1970-71 and won their Gold Medal of in 1977. After his death in London, the same institution began their Kerensky Memorial Conferences beginning in 1988.
Kerensky was the father and namesake of dance critic Oleg Kerensky, Jr (1930–1993). Oleg Junior was in the 1981 film Reds portraying his grandfather when he was the head of the Russian Provisional Government.
- Horne, M. R. (1986). "Oleg Alexander Kerensky. 16 April 1905-25 June 1984". Biographical Memoirs of Fellows of the Royal Society. 32: 322–326. doi:10.1098/rsbm.1986.0010. JSTOR 770115.