Theresa M. Hannon says 2008 and 2009 were the worst years of her business life. A dear friend committed suicide. That would be bad enough for some people, but Hannon was also her friend's succession planner, and she suddenly found herself without warning having to take over his entire practice.

It wasn't enough that the entire financial world during those two years was falling into chaos, and Hannon's firm was affiliated with the troubled insurance giant whose near-demise symbolized the market's upheaval: AIG.

Yet she emerged from these two awful years with a growing business, a devoted staff and loyal clients who cannot say enough nice things about her.

"I have never seen Terry without a smile," says Michael Bell, president and CEO of Curian Capital, a Denver-based managed accounts provider Hannon works with as a registered advisor. "Even when she was in the middle of her worst times, working 90 hours a week trying to keep the business going and assure her and her former associate's clients that everything would work out, she always had a smile on her face."

Amid the drama, the firm she founded, Theresa Hannon Financial Group Ltd. in Wheaton, Ill., has thrived, growing from $25 million in assets under management in 2003 to $60 million in 2008, and reaching just over $100 million today.

It's not a small note that Hannon is also a single mother raising four children in a home next to her office. (Many clients know her children almost as well as they know her.) And the fact that she's a woman hasn't made her career necessarily easier.

Hannon was recently handed an award for her work as an advisor by Curian Capital and noticed at the awards presentation that she was the only woman in the room. "We sometimes have to work harder to win people's trust and achieve the credibility of men," she says.

Her background has proved essential to her firm's success, but that wasn't a straight road either. Hannon graduated from Benedictine University in 1982. She had gone to college to become an accountant, but her father, who was in insurance, suggested she get a license in that, too. She said at the time she would never use it.

After she started doing tax work, however, she got a call from John Hancock with an offer she couldn't refuse: $40,000 a year to work in the company's financial planning unit. At the time she was making $17,000. Her boss told her that she needed to have a securities license to be employed there, and she got it thinking, once again, here was something she would never use.

Turns out she would need both licenses when she started her own accounting and financial planning practice in 1985. She finally sold the tax practice in 2003 to focus on the latter.