Prior to joining Santa Clara University (SCU) in 1975, Lewis worked for six years at General Electric's Aerospace Division where he designed a fault-tolerant clocking system for one of the first triple-redundant automatic landing systems for commercial aircraft. He has consulted for a number of Bay Area companies, including the Singer-Link Company, where his design of new algorithms and a corresponding modular array of VLSI circuits became the basis of a new product line of real-time computer graphics systems. Lewis' efforts led to the creation of SCU's Computer Engineering department in 1988, serving as its chair for the first 18 years. Lewis is the 2010 recipient of SCU's Brutacao Family Foundation Award for Curriculum Innovation, and author of three books, Fundamentals of Embedded Software: Where C and Assembly Meet, which has been published in four languages and received national recognition in the 2003 Alpha Sigma Nu book competition, Fundamentals of Embedded Software with the ARM(R) Cortex-M3, which has been published in two languages, and ARM Assembly for Embedded Applications.