Weider was born in Montreal, Quebec, Canada, to Louis and Anna, Jewish immigrants from Poland. He published the first issue of Your Physique magazine in 1936 when he was 17 years old, and built a set of barbells out of car wheels and axles the same year out of the family garage on Coloniale street in Montreal. He designed numerous training courses beginning in the 1950s, including the Weider System of Bodybuilding.

He married Hedwiges “Vicky” Uzar; together they had one child, Lydia Ross (mother to Weider’s three grandchildren), and subsequently divorced in 1960. During his marriage to Vicky Uzar he had met Betty Brosmer, who was then the highest paid pin-up girl in the U.S. In 1961 Joe and Betty married, and she began working alongside him as Betty Weider. Betty and Joe together authored books on bodybuilding. Joe, Betty and Ben together were the co-founders of the International Federation of BodyBuilders. In 1995, he appeared in the Charlton Heston and Peter Graves film, America: A Call to Greatness, directed by Warren Chaney.

The family founded Weider Nutrition in 1936, considered the first sports nutrition company. Now called Schiff Nutrition International, they were the creators of Tiger’s Milk nutrition bars and related products, one of the earliest lines of sports foods.  In 1953, Your Physique was renamed Muscle Builder magazine. The name changed again to Muscle & Fitness in 1980. Other magazines published by Weider’s publishing empire included Mr. America, Muscle Power, Shape magazine, Fit Pregnancy, Men’s Fitness, Living Fit, Prime Health and Fitness, Cooks, Senior Golfer, and Flex, in addition to the more risque Jem Magazine and Monsieur. The last two publications caused at least two clashes with obscenity laws. Weider has written numerous books, including The Weider System of Bodybuilding (1981), and co-wrote the 2006 biography Brothers Of Iron with Ben Weider. In 1983, Weider was named “Publisher of the Year” by The Periodical and Book Association. In 2003, his publication company, Weider Publications, was sold to American Media.

In 1972, Weider and his brother Ben found themselves a target of an investigation led by U.S. Postal Inspectors. The investigation involved the claims regarding their nutritional supplement Weider Formula No. 7. The product was a weight-gainer that featured a young Arnold Schwarzenegger on the label. The actual claim centered on consumers being able to “gain a pound per day” in mass. Following an appeal wherein Schwarzenegger testified, Weider was forced to alter his marketing and claims. Also in 1972, Weider encountered legal problems for claims made in his booklet Be a Destructive Self-Defense Fighter in Just 12 Short Lessons.

Weider was ordered to offer a refund to 100,000 customers of a “five-minute body shaper” that was claimed to offer significant weight loss after just minutes a day of use. The claims, along with misleading “before and after” photographs, were deemed false advertising by a Superior Court Judge in 1976.  In the 1980s, Weider found himself answering charges levied by the Federal Trade Commission (FTC). In 1984, the FTC charged that ads for Weider’s Anabolic Mega-Pak (containing amino acids, minerals, vitamins, and herbs) and Dynamic Life Essence (an amino acid product) had been misleading. The FTC complaint was settled in 1985 when Weider and his company agreed not to falsely claim that the products could help build muscles or be effective substitutes for anabolic steroids. They also agreed to pay a minimum of $400,000 in refunds or, if refunds did not reach this figure, to fund research on the relationship of nutrition to muscle development.

In 2000, Weider Nutritional International settled another FTC complaint involving false claims made for alleged weight loss products. The settlement agreement called for $400,000 to be paid to the FTC and for a ban on making any unsubstantiated claims for any food, drug, dietary supplement, or program.  Weider died of heart failure on March 23, 2013 at Cedars-Sinai Medical Center in Los Angeles, California at the age of 92.