Getting to Know NYC Mayor Mike Bloomberg

Jan. 25 -- Building on the legacy of Rudolph Giuliani is not an easy undertaking. But that's what New York City Mayor Michael Bloomberg — a billionaire with no government experience — was elected to do.

In his first in-depth national television interview since being elected mayor, Bloomberg tells 20/20's Barbara Walters who he is, how he's gotten so far, and what his plan is for a city that was shattered on Sept. 11.

Following are excerpts from the interview, which will air tonight at 10 p.m. ET.

ABCNEWS' Barbara Walters: Mr. Mayor, up until now, you've had the kind of life that most people dream about: fabulously wealthy, five beautiful homes around the world … Why in the world would you want to give that up? Why did you want to be mayor?New York City Mayor Michael Bloomberg: Because you get a chance to change the world, you get a chance to make a difference. I always find that question to a be a funny question: Why would you not want to have the greatest job arguably in the whole world?

Walters: Are there Bloomberg's rules for success that anyone can follow?

Bloomberg: Work hard. The harder you work, the luckier you get, it's amazing. I've always thought that a lot of my success was I just came in earlier and I stayed later. I cared more, I focused, and that's one of the things. The second is working collaboratively. I don't know any job — yours, mine, anybody else's — where you don't need other people. My lecture to kids is get rid of the words "I" and "me" and replace them with the words "we" and "us." You need to do things together. And the last thing centers around honesty. Being honest to others, it's obvious why. But being honest to yourself as well … You are who you are and then make the most of it. Don't try to be somebody that you don't have the skills to be.

Walters: Do you have a temper?

Bloomberg: Yeah, sure. I've never liked anybody that didn't. We all have tempers. If you don't have a temper, you don't have any passion.