The company was an early investor in more than 300 information technology and biotech firms, including Amazon.com, AOL, Electronic Arts, Flextronics, Genentech, Google, Hybritech, Intuit, Lotus Development, LSI Logic, Macromedia, Netscape, Quantum, Segway, Sun Microsystems and Tandem.
In 1938, he fled with his family from Vienna, Austria, arriving in New York two years later. He served in the U.S. Army, then earned a B.S.M.E. from the Polytechnic University of New York in 1948 and a M.S.I.E. from New York University. After briefly teaching engineering, he joined Western Electric, the manufacturing arm of AT&T.
In 1947, he married the former Rose Wassertheil (d. 2001), a Polish emigré. They had two children, Robert and Lisa.
In 1956, he was among the first to accept an offer from William Shockley to come to California to help form what became Shockley Semiconductor Laboratory. In 1957, he and seven colleagues (the "Fairchild Eight", whom Shockley dubbed the "Traitorous Eight") left to found Fairchild Semiconductor, which most historians mark as the first major spin-off of what later was called Silicon Valley. According to fellow VC Arthur Rock, Kleiner led the Eight, obtaining a $1.5 million investment from Sherman Fairchild and taking over the new firm's administrative duties.
In 1972 he joined Hewlett-Packard veteran Tom Perkins to found Kleiner Perkins, the venture capital firm now headquartered on Sand Hill Road. In 1977, the company added Brook Byers and Frank Caulfield as named partners. He retired from day-to-day responsibilities in the early 1980s.