Born in Philadelphia, Pennsylvania, Masterson received a Bachelor of Arts degree from Harvard University in 1949 and a Bachelor of Laws from the University of Pennsylvania Law School in 1952.
He was in private practice in Philadelphia and an instructor at Seton Hall University School of Law from 1953 to 1956.
He became an assistant District Attorney of Philadelphia 1956 and was deputy city solicitor from 1956 to 1960.
[1] Masterson was nominated by President Lyndon B. Johnson on January 16, 1967, to the United States District Court for the Eastern District of Pennsylvania, to a new seat created by 80 Stat.
[1] Following his resignation from the federal bench, Masterson was in private practice in Philadelphia until his death on June 15, 2000, in Bryn Mawr, Pennsylvania.