Born in Galveston, Texas, McMaster graduated from Houston's Lamar High School before joining the United States Army Air Corps. Stationed in Europe during World War II, he served as a bomber pilot and flew cargo planes, before returning to the United States to take up a place at the University of Houston, where he studied airport administration. He had also completed his degree when his father-in-law, a lawyer in Port Arthur, suggested he follow a legal career. McMaster studied at Houston Law School, and was a member of the school's first graduating class. After working as a defense lawyer for twelve years, McMaster joined the Harris County district attorney's office, where he became an assistant district attorney.[2] He spent eleven years in the post of assistant district attorney, becoming Chief Prosecutor, and Chief of the Grand Jury Division,[3] before he was elected as a District Judge in 1972.[2]
McMaster served as a district judge in the 179th Criminal Court for sixteen years, retiring from the bench in 1988. He presided over a number of famous cases during his legal career. Perhaps his most notable was as a prosecutor of the 1971 murder trial of Dr. John Hill, a Houston physician accused of poisoning his wife, Joan Robinson Hill. The case ended in a mistrial. Other notable cases included the trial of Harris County Commissioner Bob Eckels, accused of stealing bridge timbers, and David Port, who was indicted for the murder of a Houston letter carrier. After leaving the bench, McMaster continued to practice law, before finally retiring in 1999. He died at his home in La Marque, Texas, on June 23, 2004.[2]