Steinberg studied sociology and psychology at the University of Bucharest and architecture in Milan. From 1936 to 1939 he published his cartoons in Italian magazines. Settling in New York City in 1942, Steinberg worked as a freelance artist, cartoonist, and illustrator, mainly for The New Yorker magazine, and exhibited his drawings in Paris, New York City, and other cities. Steinberg's subject matter ranges from the whimsical (e.g., a wicker chair overtaken by its curlicues) to the satirical (sinister, overgrown gadgets) to the philosophical (a tiny figure perched on a giant question mark balanced at the edge of an abyss).