Szolem Mandelbrojt was born on 10 January 1899 in Warsaw, Poland into a Jewish family of Lithuanian descent.

He was initially educated in Warsaw, then in 1919 he moved to Kharkov, Ukraine (then USSR) and spent a year as a student of the Russian mathematician Sergei Bernstein.

In December 1934 Mandelbrojt co-founded the Nicolas Bourbaki group of mathematicians, of which he was a member until World War II.

In 1939 he fought for France when the country was invaded by the Nazis, then in 1940, along with many scientists helped by Louis Rapkine and the Rockefeller Foundation, Mandelbrojt relocated to the United States, taking up a position at the Rice Institute.

Shmuel Agmon, Jean-Pierre Kahane, Yitzhak Katznelson, Paul Malliavin and George Piranian are among his students.