John joined Greylock as a partner in 2011. John is currently on the Board of Directors of ClearSlide, Jack Mobile, Sparks Mobile, Code for America, and several unannounced investments. He leads Greylock’s investment in Dropbox and led our investments in Tumblr and Instagram. John previously served on the boards of directors of TripIt , CenterRun, and Reactivity.

Prior to Greylock, John was CEO of Mozilla, the organization behind Firefox, the open source Web browser used by more than 450 million people. John also co-founded Reactivity, an enterprise security infrastructure company acquired by Cisco in 2007, where he served as founding CEO and later CTO. Earlier in his career, John held positions on the executive team at Trilogy Software and as a Senior Scientist in Apple’s research labs.

John holds a BS in Computer Systems Engineering and an MS in Computer Science with a focus on Human Computer Interaction, both from Stanford University. He is a Consulting Assistant Professor at Stanford’s d.school, and an advisor to both the Stanford Technology Ventures Program and StartX, Stanford’s start up accelerator.