Newmyer died Monday of a heart attack while he was working out at a gym in Toronto, his friends said.
Newmyer, who had more than two dozen movie credits, was known for his passion for making both big studio pictures and independent films.
"He liked to move people," Jeffrey Silver, his partner at Outlaw Productions, told the Los Angeles Times. "He liked to make them laugh, and he liked to make them cry."
Newmyer started off as a vice president of production and acquisitions at Columbia Pictures. He and Silver formed Outlaw Productions in the late 1980s, which was named after Newmyer's favorite Clint Eastwood character, the outlaw Josey Wales.
They hit it big with "sex, lies and videotape" in 1989 and the company took off when it produced "The Santa Clause" in 1994.
This year, Newmyer mortgaged his homes in Los Angeles and Telluride, Colo., to raise $3 million to finance "Phat Girlz," a romantic comedy about an aspiring plus-size fashion designer starring MoNique Imes-Jackson. Fox Searchlight Pictures acquired the film, which is scheduled to be released in April.
"Bobby was a true maverick and a true risk-taker," said Amy Pascal, chairwoman of Sony Motion Pictures Group. "He was unlike anyone else. He put all his cards on the table."
One of his pending projects — "The Lost Boys of the Sudan" — developed from a "60 Minutes" segment about a group of young boys who were trying to flee the violence in the African country. He was so moved by their stories that he housed some of the boys in his home over the last several years, said Lucy Fisher, his cousin and fellow movie producer.
Newmyer is survived by his wife, Deborah, and his children, Sofi, Teddy, James and Billi.