LaLanne died of respiratory failure due to pneumonia Sunday afternoon at his home in Morro Bay on California's central coast, his longtime agent Rick Hersh said.
Lalanne ate healthy and exercised every day of his life up until the end, Hersh said.
"I have not only lost my husband and a great American icon, but the best friend and most loving partner anyone could ever hope for," Elaine LaLanne, Lalanne's wife of 51 years and a frequent partner in his television appearances, said in a written statement.
LaLanne credited a sudden interest in fitness with transforming his life as a teen, and he worked tirelessly over the next eight decades to transform others' lives, too.
"The only way you can hurt the body is not use it," LaLanne said. "Inactivity is the killer and, remember, it's never too late."
His workout show was a television staple from the 1950s to the '70s. LaLanne and his dog Happy encouraged kids to wake their mothers and drag them in front of the television set. He developed exercises that used no special equipment, just a chair and a towel.
He also founded a chain of fitness studios that bore his name and in recent years touted the value of raw fruit and vegetables as he helped market a machine called Jack LaLanne's Power Juicer.
In addition to his wife, he is survived by two sons, Dan and Jon, and a daughter, Yvonne.