Green attended New Roads High School in Santa Monica, California. He graduated from the University of California, Santa Barbara (UCSB) in 2006 with a B.A. in Business Economics. While a student, Green created The Green Initiative Fund, served as a board member for the Isla Vista Recreation and Park District, and was the youngest director for the Santa Barbara Metropolitan Transit District. From August 2007 to February 2008, Green was the Sustainability Director at UCSB. In 2007, alongside John Zimmer, Green founded Zimride, a ride-sharing platform that coordinated carpools, especially across college campuses.
After realizing the limits of public transportation, Green started a car-sharing program and asked Zipcar to place cars at UCSB. Because the company only had 100 cars at the time and was based on the East Coast, it couldn't provide any vehicles. Instead, Green acquired several Toyota Prius cars and other vehicles and began a car-sharing program that let users unlock cars with radio-frequency identification. The program had over 2,000 people on campus sharing four cars.
In 2006, Green was inspired by a post-college trip to Zimbabwe in which he saw locals using crowdsourced carpool networks for transportation. Using the Facebook API, he developed a platform that allowed users to find and plan carpools. He named his app Zimride in honor of Zimbabwe's carpooling network.
In 2012, Green and Zimmer shifted the company's focus to their bigger mission of providing an alternative to car ownership. 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.
In May 2013, the company reincorporated as Lyft and sold Zimride to Enterprise Holdings.
As of 2017, Green and Zimmer have raised $4.1 billion dollars for Lyft, valuing the company at $11.5 billion. The company debuted on the NASDAQ exchange in March 2019, with a value of $24.3 billion.