He was member of the princely Trubetskoy family, son of Prince Nikolai Nikolaievich Troubetzkoy (1867–1949) and the countess Jekaterina Mikhailovna Mussin-Pushkin (1884–1972). His brother, Youcca Troubetzkoy (1905–92), was an actor in French film during the 1920s and 1930s.
Being a good skier and athlete (cycling) in younger years, Igor started automobile racing in 1947 in a Simca-Gordini, taking a bronze at the Coupe de l'Agaci (Oct 26, 1947).
- Spider Corsa, #006I open 2-seater by Allemano, cycle fenders and lamps (raced by Clemente Biondetti and Tazio Nuvolari in his last Mille Miglia)
- Spider Corsa, #010I (ex-#01C) open 1-seater track car. Igor raced this in 1948.
- Spider Sport, #001S by Allemano, open 2-seater, road-registered in which Igor won Targa Florio (April 3, 1948) with Clemente Biondetti.
He retired from racing due to an accident at Circuit d'Albi (Aug 29, 1948). Sterzi had left the Scuderia and it ceased to exist, but the name was used for Ferrari 166 Inter, the company's first Grand Touring car.
He was married to American heiress Barbara Hutton (1912–79) in May 1947 and inspired her son Lance Reventlow (1936–72) to take up racing from an earlier marriage. After their divorce in 1951, Igor took up painting. In 1953, he fathered a son Arnaud Marie, who in the 1970s started Troubetzkoy Painings (Paris, New York City) that makes replica paintings.
- 166 Spyder Corsa 001S from barchetta.cc, last accessed on Nov 19, 2016.
- Biography of Igor Troubetzkoy from historicracing.com, last accessed on Nov 19, 2016.
- Years of birth and death for Igor's parents are from the Екатерина Михайловна кн. Трубецкая at Geni.com, last accessed on November 19, 2017.
- Coupes de l'Agici at racingsportscars.com, last accessed November 17, 2016.
- Targa Florio 1948 166 SC, a discussion at ferrarichat.com, last read on Nov 17, 2016.
- 166 Spyder Corsa 006i at barchetta.cc, last accessed Nov 19, 2016.
- 01C 125C Spyder in barchetta.cc, last accessed Nov 10, 2016.
- 010I 166 Spyder Corsa at www.barchetta.cc, last accessed November 19, 2016.
- Prince Igor Troubetzkoy in ferrarichat.com, last accessed on Nov 19, 2016.
- "Troubetzkoy Paintings". troubetzkoypaintings.com. Retrieved 21 November 2016.