Leone was born July 4, 1957, in Genoa, Italy. His family moved to the United States when Leone was 11 and settled in Mount Vernon, New York. Leone earned a Bachelor of Science in mechanical engineering from Cornell University in 1979, a Master of Science in industrial engineering from Columbia University in 1986, and a master’s degree in management from the MIT Sloan School of Management in 1988.

Leone began his career in sales and management positions at Sun Microsystems, Hewlett-Packard, and Prime Computer. He joined Sequoia Capital in 1988, became a managing partner in 1996, and became the global managing partner in 2012. In 2017, Forbes named him a top-10 investor in the technology industry in the United States. He led Sequoia’s international expansion into China and India. Leone was responsible for investments including ServiceNow, Aruba, Meraki, Rackspace, Netezza, Arbor/Hyperion, RingCentral and MedExpress. He sits on the board of PlanGrid, NuBank, Medallia, ZirMed, ActionIQ, Numerify, and Lattice Engines. In 2017, he was ranked #693 on Forbes list of the World’s Billionaires, with a net worth of US$2.9 billion. In 2020, he was named on the Forbes Billionaires list with wealth of US$3.5 billion and ranked #538.