Weider was born on November 29, 1919 in Montreal, Quebec, Canada to a Polish-Jewish family. He was raised in Los Angeles, California. His brother was Ben Weider. Weider was married to Betty Brosmer from 1961 until his death in 2013. They had no children. Weider died on March 23, 2013 from heart failure in Los Angeles, California, aged 93.