Sax was born and raised in Peoria, Illinois. He graduated from Brown's Business College (now Midstate College) in Peoria.
In 1944, Sax took over Halsted Exchange National Bank after purchasing a controlling share. He renamed the bank The Exchange National Bank of Chicago and moved it to downtown Chicago.
Sax is credited with the innovation of several banking practices that have since been adopted worldwide - drive-through banking and instant loans. Later in his banking career, Sax devised such practices as open credit accounts. The Exchange National Bank had 10 teller windows and was the first in the Loop to feature show windows. The Sax family maintained control of Exchange for over thirty years.
After World War II, Sax was involved in another business venture - the building of the Saxony Hotel. The Saxony was the very first luxury hotel built in Miami Beach and was the first hotel to have central air-conditioning. Among the most lavish resorts in the country, the Saxony was frequently used by heads of state and featured rooms with glorious views, air conditioning, and complementary meals.
His granddaughter, Anita Sax, is a children's book author and publisher. Anita Sax was born in Chicago, Illinois and raised in Mexico City, Mexico. Her passion for writing began at a young age after a school project led her to write her first short story. She has been writing ever since.