Nabors, 82, is best known for his work on TV's "Gomer Pyle, USMC." Cadwallader, 64, is a retired firefighter.
"I'm 82 and he's in his 60s, and so we've been together for 38 years and I'm not ashamed of people knowing," Nabors told Hawaii News Now. "It's just that it was such a personal thing, I didn't tell anybody."
The couple were married before a judge and some neighbors from Hawaii at the Fairmont Olympic Hotel in Seattle, People.com said.
"I'm very happy that I've had a partner of 38 years and I feel very blessed," Nabors said. "And, what can I tell you, I'm just very happy."