[13] In 2007, alongside John Zimmer, Green founded Zimride, a ride-sharing platform that coordinated carpools, especially across college campuses.

[13] While attending college in Santa Barbara, he used public transportation options like Greyhound and Amtrak to visit his girlfriend in Los Angeles.

[15] After realizing public transportation's limits, Green started a car-sharing program and asked Zipcar to place cars at UCSB.

[19] Green had posted details about his new company called Zimride, which interested Zimmer, who had been keeping a journal about carpooling ideas.

[20] Zimride launched the first version of its ride-share program at Cornell University where, after six months, the service had signed up 20% of the student body.

[23] Green and Zimmer promoted the service through guerrilla marketing campaigns; in particular, the pair would dress in frog suits and hand out flyers to students on the Cornell campus.

[20] Green and Zimmer moved to Silicon Valley to work on growing the company, sharing an apartment that doubled as their office.

That year, the company launched a smartphone app that allowed users to request rides more frequently and for shorter commutes rather than long-distance trips as Zimride had previously done.