Donald Trump’s supporters often point to his experience as a successful businessman to bolster their case that the GOP nominee has the right qualifications to be president. It's true that Trump has devoted entire books to chronicling his business successes, but as democrats and others launch attacks on Trump’s business credentials -- and question whether he’s really as business savvy as he says he is -- another presidential candidate who built his career and his fortune on his business acumen is garnering increasing attention. Meet Gary Johnson, the libertarian party’s nominee for president.

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Johnson spent the first two decades of his career building a construction business from scratch. When he started Big J Enterprises in 1976 in New Mexico, he was the company’s only employee. Johnson grew his business into a multimillion-dollar company with more than 1,000 employees, selling it for $10 million in 1999, a few years after being elected governor of New Mexico.

Later in life, Johnson started the nonprofit advocacy organization, Our America Initiative, to promote free-enterprise ideals. He also served for a year-and-a-half as CEO of Cannibis Sativa, a Nevada company that manufactures and sells legal marijuana products. In a June op-ed piece, Fortune magazine proclaimed that Johnson might be “ the closest thing the business community has to a candidate” and “corporate America’s best bet for president.”

Johnson credits much of his success to the business skills he’s honed and perfected throughout his life. He says his guiding principles for navigating the business world are the same ones that he now uses to navigate the political world. I sat down with Johnson recently to talk about his advice for succeeding in business. Here are his top four tips:

1. Always keep your word.

Johnson says when you promise something, you need to deliver on it, and you need to do so on time and under budget. When he was governor of New Mexico, he routinely vetoed bills that he believed the state didn’t need and couldn’t afford -- 750 in all -- earning him the nickname “Governor Veto,” a badge he wears with pride. “Do what you say you’re going to do for people,” he told me. “Given the fact that I did business for thousands in Albuquerque (as New Mexico’s governor), you would think someone would complain somewhere. No one complained because I made right by everybody.”

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2. Always tell the truth.

Johnson says that he has never shied away from sharing the truth, even when it was politically unpopular. He is one of the most high-profile political voices advocating legalizing marijuana, and he’s been vocal about this long before mainstream Americans began coming around to the idea. His approval rating took a hit when he announced his support in the 1990s for marijuana legalization -- a shocking position at the time for a Republican governor at the time -- but it didn’t faze him. “If you tell the truth, you don’t have to remember anything,” Johnson told me. “It’s hard to do damage to someone who is telling the truth.”

3. Always be on time.

Johnson views being on time as central to a strong work ethic. He was born in rural North Dakota to working-class parents, an experience that informed his views on work ethic. “Everybody’s on time,” he told the Fargo Inforum newspaper, describing the values of the people from his hometown. “There's just an unquestioned work ethic… Just the whole honesty, integrity -- that's what was ingrained in my life.” In my conversation with him, he also emphasized the importance of being on time. “I show up on time to a fault.”

4. Always admit your mistakes.

Johnson says he’s never been shy about acknowledging his mistakes and doing whatever he can to make right by them. At a presidential town hall forum in August, Johnson declared that the Black Lives Matter movement had helped him realize his “head’s been in the sand” on the issue of racial prejudice. “I think we’ve all had our heads in the sand,” he said during the forum. “And let’s wake up. This discrimination does exist.”

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Johnson is hoping the skills and acumen he’s honed through his experience in business will parlay into his most successful run for president yet. He ran on the libertarian party ticket in 2012 and earned about 1 percent of the popular vote, an accomplishment he’s hoping to build on significantly in 2016. Along the way, he’ll be taking his own best advice as he works hard to keep his commitments, be truthful, be on time, and admit when he’s made a mistake.