"It's a secret ballot," he told reporters after speaking at Harvard's Kennedy School on Thursday. "I haven't made up my mind what I'm going to do."
The New York Daily News reported
that Bush hinted he was going to vote for Johnson at an event hosted by the Manhattan Institute on Wednesday. He reportedly joked about "President Johnson" and mouthed the nominee's name to a man who said he didn't want to vote for either major political party nominee.
"I don't think so," the former Florida governor said, when asked Thursday if he mouthed Johnson's name as described in the article.
Bush routinely says -- and repeated it again on Thursday -- that he's not going to vote for Republican Donald Trump or Democrat Hillary Clinton.
"I'm at peace with my decision," he said, saying neither meet the "threshold" of the presidency. "It's not a binary choice for me."
Bush said he's not being "derelict in my civic duties" and vowed to still vote for someone. "The presidency is a place where, for whatever reason, I'm not comfortable supporting either party's nominee."
Asked what would happen if the average voter took his stance and didn't vote for Clinton or Trump, Bush said such an act would send a signal.
"Well, if everybody didn't vote, that would be a pretty powerful political statement, wouldn't it?"
Johnson, who's reached as high as 10% in some polls, has come under heat lately for making mistakes in interviews. On MSNBC Wednesday, he failed to name a world leader
that he admired, a gaffe that came just weeks after he didn't recognize the city of Aleppo that rests at the heart of the Syrian civil war.
Bush was also asked about his father's decision to vote for Hillary Clinton. The former governor expressed frustration at Kathleen Hartington Kennedy Townsend, though he didn't mention her by name, for breaking the news by posting about it on Facebook following a private event she attended with the former president.
"I thought it was a little inappropriate for a person to overhear a frail, 92-year-old man, in a private setting, at a reception for the Points of Light foundation -- which focuses on volunteerism -- to hear this and immediately go on Facebook and put it on there and then go on national television and not even show up at the board meeting," he said. "I thought that was inappropriate."
Bush's speech Thursday night is part of a multi-visit commitment this fall to speak about education policy as a guest lecturer.
His remarks Thursday night were focused more broadly on his ideas to address poverty. While he fielded questions from the audience about the substance of his speech, he also got a few political questions.
One student started off a question saying, "This has obviously been a tough election cycle,"
"Tell me about it," Bush deadpanned, drawing laughs as he sipped from a glass of water. "I'm going to give you a nickname like my brother does: 'Captain Obvious.'"
The student went on to ask about Bush's thoughts on Trump saying the political process is "rigged" against candidates like him.
"Trump only talks about things being rigged when it's not going well for him," Bush said, again drawing laughs. "When things are going well, all of a sudden the system looks pretty good, it's working well. I guess that's human nature. So you can measure how he thinks the campaign is going by the rapidity of whether it's rigged or not. That's a leading indicator."
It's no secret that Bush holds low regard for the Republican nominee, a man who Bush says rose to prominence by feeding off of voters' fears rather than their hopes.
He acknowledged that his unsuccessful bid was "really disappointing" and reiterated lines from his stump speech calling for the restoration of "civility."
"I'm not going to change who I am. I'm not going to be angry," he said. "I'm committed to my views and I fight for my views, but the idea that you're weak if you're warm-hearted or you believe that someone that disagrees with you is an evil person, man we got to stop that. That is just dangerous for our democracy."
Bush also spoke at length about racial tension in the country, suggesting repeatedly that criminal justice reform measures may be one step in easing some of the anxiety between law enforcement and minority communities.
Talking about Colin Kaepernick -- the San Francisco 49ers quarterback who kneels during the national anthem out of protest, saying the country oppresses African-Americans -- Bush said he's "troubled" by his decision but respects "his right to do it."
"But all the sports commentators that are talking about it say we are going to have a conversation about it," he said. "Well we don't, we just say we're having a conversation about it. I've not heard one tangible thing said on television about this issue, how we can solve it and I think we truly do have to have a set of policies that change it."