FORTUNE — Among the happiest of the investors behind Google’s (GOOG) move to buy Nest Labs for $3.2 billion earlier this week is the venture capital firm Kleiner Perkins Caufield & Byers, which is believed to be the company’s largest outside shareholder. The deal will likely return the firm 20 times its original investment, a win for a superstar firm that has seen middling returns for the better part of the last decade.
Most of the credit for this deal has gone to Randy Komisar, the Kleiner Perkins partner who biked with Nest Labs cofounder Tony Fadell on the weekends long before they did a deal together, and later sat on the board of the company. But there’s another partner who deserves some credit as well. Trae Vassallo played a big role in landing the deal for Kleiner Perkins, and she was very involved in the company’s management early on.
Born in Minnesota, Vassallo has both a master’s degree in mechanical engineering and an MBA from Stanford University. She also holds 13 patents. Vassallo began her career at the design firm IDEO, where she worked on projects for Dell and Palm. (She helped design the iconic Palm V). After joining Kleiner Perkins as an entrepreneur-in-residence in 2003, she cofounded the Kleiner-funded mobile software company Good Technology, which sold to Motorola in 2006. She has been with the firm ever since.
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Vassallo was very involved in building out Kleiner’s greentech strategy. Partly because of their long and uncertain time horizons, these investments have been held responsible for the firm’s dismal returns over the last decade. Critics complained that such investments distracted partners from the big digital bets like Facebook (FB). Nest Labs, along with software company OPower where Vassallo is a board observer, were the exceptions: green companies with a more digital focus.
Vassallo had been obsessed with thermostats well before she and and Komisar met former Apple executive Tony Fadell. She’d spent time with energy companies like Silver Spring Networks and Enphase (both now Kleiner investments) that were focused on bringing intelligence into network. She’d also started to see companies in partnership with utilities attempt to develop products for the home. She described thermometers people could put on their counters to show how many kilowats a person used at one time. “It’s easy to see why these products all failed,” she said. No one wants to buy something sold through a utility.
Vassallo knew Fadell from Apple networks, so when he and cofounder Matt Rogers came in to pitch the idea to her and Komisar, she knew it made sense. “They got consumers,” she said. “And the only people who could build this kind of product were people who could build a smartphone.” Vassallo negotiated the series A round on behalf of Kleiner Perkins, and then supported the management team through introductions to utilities, particularly in the competitive Texas market.
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Kleiner has Vassallo partly to thank for the Nest win, but it may not have her for that much longer. When the firm reorganized its management last year, Vasallo was no longer part of the early-stage investment committee.
When asked whether she plans to stay at Kleiner, she offers only this slightly cryptic response: “I’m at Kleiner now and focused 100% on my companies and entrepreneurs,” adding, “The most important thing for me is to continue to meet and work with the best people.” Wherever that may be.
