During his acting career, Lau was probably best known as Lt. Andy Anderson in the series Perry Mason. He appeared frequently during the latter part of the show's run, especially during times when longtime series regular Ray Collins, who played Lt. Arthur Tragg, was absent. (Collins died in 1965 before the series ended its run.) Lau first appeared on Perry Mason as defendant Amory Fallon in "The Case of the Impatient Partner" in September 1961. Less than a month later, he made the first of 81 appearances as Lt. Anderson, a role which ran from the fourth episode ("The Case of the Malicious Mariner") of the fifth season (1961–1962) through the last episode ("The Case of the Mischievous Doll") of the eighth season (1964–1965).