Alexander Solomon Wiener was born in Brooklyn, New York, the son of George Wiener, an attorney who had emigrated from Russia in 1903, and Mollie (Zuckerman) Wiener. He attended Brooklyn public schools, graduating from Brooklyn Boys' High School at the age of 15. He was awarded scholarships to attend Cornell University where he continued his study of mathematics and even contributed mathematical problems to the American Mathematical Monthly. He majored in biology, however, receiving his A.B. in 1926. He then entered the Long Island College of Medicine where he was awarded an M.D. in 1930.