Former Zipcar CEO Scott Griffith joined VC firm General Catalyst’s Cambridge office as an XIR and partner on Tuesday.

Griffith first became involved with General Catalyst last spring, when he joined the board of Boston sports coach marketplace app CoachUp. After leaving Zipcar and taking a moment to “catch his breath,” Griffith will put his experience building great companies and entrepreneurial background to use in the new role.

General Catalyst’s XIR program pairs up savvy executives-turned-partners like Griffith with founders at the firm’s portfolio companies. XIRs work with the scaling startups two to three days a week from the perspective of a mentor, and provide advice around revenue growth, C-level hiring, mergers and acquisition strategy and more.

“I know first hand that it can be very lonely at the top when you’re running one of these high growth companies,” Griffith tells BostInno. “Many founders don’t have that collaborative relationship with anyone of their board.”

Griffith will make around two to three investments a year in three main fields: the marketplace model, the connected car space, and small business empowerment. The new XIR already has his hands in the first space through his time spent with Zipcar, CoachUp and TaskRabbit, which is now based in San Francisco. TaskRabbit CEO and founder Leah Busque hatched the popular peer-to-peer marketplace for small jobs and errands in Zipcar’s offices back in 2008, noted Griffith.

Griffith served as Zipcar’s CEO from 2003 to 2013 and grew the firm from $2 million in revenue to nearly $300 million in revenue through organic growth and acquisitions before taking the car marketplace public in 2011. The company was then sold last year to Avis Budget Company for around $500 million.

Of all the lessons learned from his tenure at Zipcar, Griffith hopes to bring his understanding of leadership dynamics and team growth to the table at General Catalyst. Explained Griffith:

The powerful difference between a big idea and a big company is mostly influenced by the team you have. Really helping at the XIR level and building great teams and high performance cultures within those companies is really something that I’m looking forward to. Some of my worst mistakes [at Zipcar] were in hiring or team issues that I didn’t deal with fast enough. Being proactive and aggressive with hiring … is one of the best lessons I have from Zipcar.

Griffith is the second XIR hire that General Catalyst has made in 2014. Paul Sagan, the former CEO of Cambridge’s Akamai Technologies and Time Warner, joined the firm in an XIR capacity in mid-January. Sagan made his first investment in a $16.5 million round for New York City-based digital media consulting firm L2 in March.

Hopefully Boston startups, too, will begin reaping the benefits of Sagan and Griffith at General Catalyst.

“Boston is as hot as it’s ever been,” said Griffith. “Historically, Boston has been focused on the enterprise, and some other aspects of technology, but we’re really getting our footing in the consumer and ecommerce space … It’s a really exciting time.”