Davis' wife, Mimi Raleigh, confirmed his death to The New York Times.
Davis was a longtime collaborator of fellow "SNL" alum, now U.S. Sen. Al Franken, D-Minn. The two worked as a comedy duo from the 1970s to 1990 when Franken ended their professional partnership due to Davis' drug use, the Times said.
Davis wrote for "SNL" from 1975 to 1980 and from 1986 to 1994. Along the way he helped create the iconic Coneheads and worked closely with Dan Aykroyd on his classic impersonation of celebrity chef Julia Child.
The Minneapolis native shared three Emmy Awards for his writing on the show and another for "The Paul Simon Special" in 1977.
He chronicled his career in the 2009 memoir, "Thirty-Nine Years of Short-Term Memory Loss: The Early Days of SNL From Someone Who Was There."
One of his last efforts was helping Aykroyd with his script for a possible "Ghostbusters III" film.
Davis is survived by his wife; his brother, Robert; and his mother, Jean Davis, the Times said.