The resume 'green flag' Kevin O'Leary looks for that has nothing to do with a candidate's skill set

When Kevin O'Leary is flipping through resumes to fill an open role, there's one "green flag" he looks for that has nothing to do with the applicant's ability to do the job.

In O'Leary's view, the greatest talents and managers have a balance that he dubs "yin and yang." He likes when candidates are well-rounded, such as a person who is great with finances but who also enjoys playing an instrument or taking photographs, the O'Shares ETFs chairman tells CNBC Make It.

"When you see something that is completely different and polar to the skill set you're trying to hire, that's a very strong thing," he says. "It's very important because it shows that the person is balanced in the sense of how they think."

His advice is in line with that of other experts, including wealth manager John Spooner, who suggests that applicants include "at least one unusual thing" about themselves in order to add "color" to their resume and help spark conversation with hiring managers.

O'Leary says that he recently hired a candidate for a social media role who he learned practices classical ballet in the evenings. Though it had nothing to do with her ability to do the job, it made her resume stand out, O'Leary says.

"I see that as a commitment and a discipline that will be applicable in both sides of her life — in dance and in business," he says. "That's a wonderful thing to look for in resumes."

He believes that hiring managers should look beyond the cut-and-dry job qualifications when assessing their candidates and ask them about their other interests. Having time-consuming hobbies outside of work can be a sign that a candidate is a diligent worker, he says.

"When I see people that are balanced that way, it doesn't mean they're not working very hard — they are," he says. "They're working like crazy because they're trying to do all these things at the same time."

Candidates who are able to wow hiring managers and land the roles they want should be prepared to commit to the position for at least two years, O'Leary says. He previously said that his biggest resume "red flag" is a candidate with a history of "bouncing all over the place."

"Have a mental commitment, whether you like [the job] or you don't, to stay there for at least two years," he said last year. "If you're asking to become part of a team as an employee and represent that company, you've got to have a minimum of a 24-month commitment."