Evan McMullin opened his bid for the White House Monday morning, announcing on his website: "It's never too late to do the right thing. And if we work together, there's nothing we can't achieve."
McMullin said later Monday he decided running for president was something that "needed to be done" by a conservative -- and he saw no other options.
"I hoped for something better for months and months and months, and that somebody would step forward -- somebody with national name ID who could advance another option for Americans, a better option. But it became clear as time passed that that wasn't going to happen," he told CNN's John Berman on "AC360."
He called Trump "inhuman" and said the Republican nominee doesn't care about anyone but himself -- pointing to Trump's criticism of the Khan family, parents of a US soldier killed in combat, and Arizona Sen. John McCain, who Trump once suggested is not a war hero.
"You have to be a special kind of person to attack those that risk their life to protect you," he said.
McMullin also cast Trump as a candidate who's already lost the general election.
"Donald Trump is already losing badly to Hillary Clinton. He is a weak candidate and he's performing that way," he said.
Earlier in the day, McMullin's campaign wrote in a message to supporters: "Evan has spent his entire career in service to our nation and today he's continuing on that path as a candidate for president -- he is running first and foremost out of a deep love for this country, and because he understands the true brand of American leadership that is required to be commander in chief."
McMullin, who had been the policy director for the House Republican Conference, is a longshot for the White House at best -- facing high hurdles in the form of ballot access deadlines that have already passed in many states -- but will offer anti-Trump conservatives an alternative to Trump and Clinton.
McMullin's presence could be felt most in Utah, where anti-Trump conservatives rallied behind Ted Cruz in the primaries and McMullin has one week to make the ballot. Cruz beat Trump 69%-14% in Utah after Mitt Romney urged Republicans in the Mormon-heavy state to fight Trump.
McMullin is a graduate of Brigham Young University, the university owned and operated by the Mormon church, according to his LinkedIn profile.
Utah, which is typically a reliably red state in presidential contests, has emerged as a possible toss-up. If McMullin were to draw enough conservatives from Trump, he could possibly throw the state to Hillary Clinton.
McMullin worked for 11 years in the CIA, three years as an investment banker with Goldman Sachs, and as a top staffer on the Hill since 2013, according to his LinkedIn profile.
An aide to the Conference said Monday morning that McMullin is no longer an employee of the Conference.
Anti-Trump Republicans, led by Weekly Standard editor Bill Kristol, stumbled in earlier efforts to recruit someone to run and some of Trump's most vocal opponents, like Nebraska Sen. Ben Sasse, have ruled themselves out of running.
McMullin on Monday afternoon sought to differentiate himself from both nominees.
"Hillary Clinton is a corrupt career politician who has recklessly handled classified information in an attempt to avoid accountability and put American lives at risk including those of my former colleagues," McMullin wrote on his campaign site
And of the Republican nominee, McMullin wrote: "Donald Trump appeals to the worst fears of Americans at a time we need unity, not division. Republicans are deeply divided by a man who is perilously close to gaining the most powerful position in the world, and many rightly see him as a real threat to our Republic."