His wife, Mimi Raleigh, said he died of throat and neck cancer at his home in the Hudson Valley, north of New York City. He was diagnosed in 2009.
Davis is best known as the thinner, taller partner in Franken and Davis, the off-kilter comedy duo who performed in the early years of the show. They also were among the first writers hired for the new show in 1975 and helped create memorable work such as the "Coneheads" skit with Dan Aykroyd and what evolved into the "Nick the Lounge Singer" skit starring Bill Murray performing lounge-lizard versions of songs including the "Star Wars" theme.
Raleigh said Davis and Franken "were two of the first writers hired - with one salary."
As performers, Davis was the quiet guy, overshadowed by the flashier Franken, who is now a Democratic senator from Minnesota. Davis, in a 2009 interview with The Associated Press, said, "If we were Sonny and Cher, he would be Cher."
Franken said he spoke with Davis's mother Thursday, and she recalled fondly all the laughter that would come from the basement when the two first got started in comedy.
"I visited Tom two weeks ago, and though he was deathly ill, we did a lot of laughing," Franken said. "He was a great friend, a good man, and so funny."
Dudley Riggs, founder of a comedy theater and improv in Minneapolis where Franken and Davis got their start in the 1970s before heading to "SNL," said Davis would always find "an oblique way" to tell a joke and had "a knack to be able to surprise."
Screenwriter Pat Proft called Davis and Franken a "perfect comedy team."
"Last I saw Tom he was happy," Proft said in an email. "He wrote his book. We talked. Had a wonderful time. I'm sorry for his wife. His family. For Al. For all of us who know him. A very sad day."
Davis met Franken at a suburban prep school in Minnesota, where their first gig was making announcements at morning chapel. They hit it big with "SNL" and stayed there until 1980, then returned a few years later. Davis left the show in 1994, feeling frozen out. Still, he told the AP he would always treasure his time on the show.
"It's my family. It's my extended, dysfunctional family, and I love them," Davis said.
"SNL" creator and executive producer Lorne Michaels said "no one saw things the way that Tom did."
"He was funny, he was original and he was always there to help no matter the hour," he said. "And I always trusted his laugh. I can still kinda hear it."
In the 2009 interview with AP, Davis recalled spending his childhood watching "The Mickey Mouse Club" on television while wearing Mouseketeer Ears. He was the older of two brothers. Their father worked for 3M and their mother was the 1950 Queen of the Lakes of the Minneapolis Aquatennial, an annual summer festival.
In his memoir, "Thirty-Nine Years of Short-Term Memory Loss: The Early Days of SNL From Someone Who Was There," Davis also detailed friendships with counterculture legends Jerry Garcia and Timothy Leary, his own drug use and his travel as a young hippie to India in the 1970s.
Davis kept up his quirky sense of humor to the end, writing an essay on his experiences with cancer and the coming end of his life.
"I wake up in the morning, delighted to be waking up, read, write, feed the birds, watch sports on TV, accepting the fact that in the foreseeable future I will be a dead person," Davis wrote. "I want to remind you that dead people are people too."
Veteran "SNL" writer Jim Downey said Davis had a sense of humor different from everyone else, seeming to come out of nowhere.
"He was a loyal friend, a generous and supportive collaborator, and utterly unthreatened by the success or talent of those around him," Downey said. "His old pals have known for some time that this day was coming, but still it's hard to accept that he's now no longer out there, somewhere, thinking those crazy thoughts that no one else would think."