Billy Mayo is a character actor who has worked primarily in television, often appearing as hard-bitten cops and other stern authority figures. After playing football in high school, Mayo earned a bachelor's degree in engineering while serving in the United States Marine Corps. He moved to California, intending to pursue a career in engineering, but became interested in acting instead. His first role was on the made-for-TV movie "Murder at Midnight." More foul play followed with a stint on the long-running mystery series "Murder, She Wrote "; from there Mayo began to work steadily on episodic television, nabbing small roles on popular network dramas throughout the 1990s and well into the 2000s, with appearances on the frontier show "Dr. Quinn, Medicine Woman," the medical hit "ER," and the saccharine family series "7th Heaven." His first notable film roles came as a pilot in disaster flick "A Perfect Storm" in 2000, and two years later in the sci-fi flick "Clockstoppers" (as a government agent). In 2007, Mayo landed a recurring role on the suburban satire "Desperate Housewives" as Lyons, a police detective.