Foster served in the United States Navy during World War II.
[1] He completed his doctoral dissertation in 1951, titled The Effects of Configuration Interaction on the Hyperfine Structure, advised by Bernard Taub Feld at the Massachusetts Institute of Technology,[2] and later joined the MIT faculty.
While teaching at MIT, Foster was elected a fellow of the American Physical Society in 1962.
[3] Foster was married to Frances J. Grigg until her death in 2010.
[1][4] Foster died in Brookline, Massachusetts, in May 2012, aged 85.