Playing Superman turned out to be Dean Cain's big break, but few knew the actor's own kryptonite: The Man of Steel was afraid of heights.

It wasn't the first obstacle he'd had to overcome. The "Lois & Clark" star hadn't even meant to be an actor. A star Princeton athlete, he had signed as a free agent with the Buffalo Bills but was sidelined by a devastating knee injury in training camp, ending his NFL career.

"I was 22 years old. And I suddenly had to go, 'Oh my gosh. I have to sort of rethink who I am. Because I'm not gonna be able to be that athlete any longer,'" he said.

So when it came to overcoming fear, Cain had some experience.

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"You can make a choice in life. And you always get to this place where you can beat it or it can beat you," he said. "And that could be jumping off a bungee jump. It could be hosting a television show. It could be doing a commercial. It could be trying out for a football team. It could be any of those things."

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Dean's journey took him in unexpected directions — he's been a screenwriter, a television host and, most proudly, a single dad. He reflected on his journey with NBC News' BETTER:

Don't believe in 'no':

The best advice I ever got, and it's the best advice I'd give anybody, is just don't believe the word no. Be persistent. Persevere. Keep going. Never, ever, ever give up. People are gonna tell you a million times, "No, you can't do it. No, you can't do it. You'll never make it. You'll never do this, you'll never do that."

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Actor Dean Cain speaks about conquering his fear of heights. NBC News

Do not believe them. Always believe in yourself and keep going. You don't have to have the most talent in the world. You don't have to be the smartest person in the world. If you persist and you persist and you persist, you will be successful.

On being Superman:

The idea of playing Superman is ridiculous for anybody. ... I wasn't thinking about stepping into Christopher Reeves' shoes or his boots or the cape, so to speak. He was my Superman. For me, it was more about playing Clark Kent, who was just a regular guy — and the way I played him all the time was that he had a secret. ... It took me till the middle of the second or third season to really realize that for the rest of my life, anywhere I go, anything I do, I'll be associated with Superman.

On fatherhood:

Being a father taught me patience. And it taught me vulnerability. You don't realize how vulnerable you are when you love something else more far more than yourself. There's a saying that a lot of parents have, which is, "You're only as happy as your most unhappy child."

When I became a parent, my entire life changed. And you suddenly live for this other person. That person's health and happiness is more important than your own, at least if you're a good parent, and I believe I am a good parent. I always said I was good football player, I'm fine as an actor, but I'm a great dad.

I won't take a movie that shoots more than a month and a half anywhere. I won't do it. I haven't done it.

Success in hard work:

My credo in everything is, whatever you're gonna do, do it to the best of your ability. And take pride in it. I don't care if you're a janitor or if you're the chalkboard cleaner or if you're the C.E.O. of a company. Do the best you can at that job and take pride in your work, and you will be fulfilled.

Success to me means happiness. And being fulfilled, regardless of what you do. For some people it's money, for some people it's fame, for some people it's power. For me, it's just being the best I can be, and having those around me, my family and friends, be happy. And knowing that I've worked my hardest or tried my best.

On relationships and regret:

Looking back, there aren't a lot of things I would change in my life. I probably would've gotten out of some relationships a lot earlier than I did.

To the ladies out there: You're not gonna fix the bad boy. It doesn't happen. And the guys, you know, if she's got a wandering eye, and you catch her eye, when she's with you, she's still gonna have a wandering eye. So you kind of reap what you sow.

On overcoming fear

I am scared of heights. I do not like heights. And that includes flying. That includes staying in a hotel, say, here in New York City. Anything above, like, the 25th floor. If I see a hotel, I check into it, and they're like, "Oh, you're on the 38th floor," I'm uncomfortable. I don't like heights. Having said that, I've jumped out of helicopters. I've rappelled off, you know, hundred-foot, you know, drops and things. I don't like it. I can conquer that fear.

There's nothing in my life that I look back, and I say, "I wish I could try that again. I need a second chance, 'cause I didn't give it my all." Because I did. I gave it my all. I failed a few times, but that's part of the game.

On acceptance:

I've learned you have to accept your mortality. Your limits. And give yourself a break. You know, you're not gonna be perfect all the time. Just relax, and love who you are. And believe in yourself. And if people don't like you, well that's their fault. Just be you. Stay comfortable.