For a period of time, he concurrently served as director of system development for the Berkeley Computer Corporation (1969–1971).

In 1971, Lampson became one of the founding members of Xerox PARC, where he worked in the Computer Science Laboratory (CSL) as a principal scientist (1971–1975) and senior research fellow (1975–1983).

At PARC, Lampson helped work on many other revolutionary technologies, such as laser printer design; two-phase commit protocols; Bravo, the first WYSIWYG text formatting program; and Ethernet, the first high-speed local area network (LAN).

Shortly before Taylor's retirement, Lampson left to work for Microsoft Research as an architect (1995–1999), distinguished engineer (2000–2005) and technical fellow (2005–present).

Since 1987, Lampson has been an adjunct professor of electrical engineering and computer science at the Massachusetts Institute of Technology.