The 55-year-old former Arkansas governor and Baptist minister who was unsuccessful in his bid for the GOP nomination in 2008, made his decision known on his Fox News Channel show.
"All the factors say go, but my heart says no," Huckabee said.
Ed Rollins, who guided Huckabee's campaign, said he wasn't surprised since Huckabee had not communicated with him for about a week.
Roll Call reported Huckabee, who now lives in Florida, has declined to enter the race despite polls showing him "at or near the top" of the GOP field and having his wife's support for another run. Ultimately, he said, it was a "spiritual" choice and a decision that left him with "inexplicable inner peace."
Asked on Fox whether he felt an obligation to run, Roll Call said he replied: "The obligation is to love your country and serve it the best way you can. If that's being a candidate, then yes. If it's maybe in another role, maybe that's it."