PlayFirst, one of the leaders in casual game publishing, announced today that it has appointed a new chief executive and chief financial officer.

Mari Baker has joined as CEO, replacing founder John Welch, who is moving on to other opportunities. The San Francisco company has also appointed Jim Wandrey as chief financial officer.

Baker has more than 20 years of experience in consumer technology. She was previously chief executive of Navigenics, president of BabyCenter, and senior vice president at Intuit. PlayFirst has published some big titles in the casual game market — lighter, shorter fare for people who don’t consider themselves hardcore gamers. PlayFirst’s hits include Diner Dash and Chocolatier, and many of their fans are women.

Baker has some big shoes to fill. Welch was a casual games evangelist, often speaking at conferences and predicting that game consoles would eventually disappear due to growing demand for casual games on mass market platforms. Wandrey joined PlayFirst as CFO in late 2008, but the company is only announcing his addition now. He was previously CFO at Telephia and NextLevel Communications. He replaces Mike Dickey.

The company’s backers include Mayfield Fund. Welch founded PlayFirst in 2003 and raised $5 million in funding during the bust in Silicon Valley, often referred to as nuclear winter. This year, PlayFirst introduced Chocolatier: Decade by Design and Emerald City Confidential. It has Diaper Dash and Wandering Willows debuting in March. The company supports a range of platforms worldwide, including PC, Mac, iPhone, mobile, handheld and console markets. Games are available at major stores and on 500 sites in 20 languages.

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