Douglas C Sinclair did his undergraduate study at MIT and received his doctorate from the Institute of Optics at the University of Rochester. After receiving his Ph.D., he served as the Manager of Product Development at Spectra-Physics. In 1970, he became Professor of Optics at the Institute of Optics, where he was interested in developing software that could help students learn computer-aided optical design. He founded Sinclair Optics in 1976 to develop a software package that evolved over time to become one of the best known and widely used optical design programs.

He was an OSA Fellow and Adolph Lomb Medal recipient. Sinclair was an Emeritus member of OSA with 55 years of membership, having joined in 1960. He was Editor of the Journal of the Optical Society of America from 1976-1978, President of the Rochester Section in 1975, and Chairman of the U.S. delegation to the International Commission for Optics in 1978. 

He passed away in 2015.