He won an Emmy in 2003 for his main title theme for Star Trek: Deep Space Nine.

McCarthy began to accumulate television credits as early as the late '60s, working as an arranger and music director for TV specials and variety shows such as The Glen Campbell Goodtime Hour and Barbara Mandrell and the Mandrell Sisters. He went on to write music for series including but not limited to Enos (1980-1981), V (1984-1985), Dynasty (1985-1989), MacGyver (1958-1991), and, beginning in 1987 and through the show's seven-season run, Star Trek: The Next Generation. During that run, he also co-produced and co-arranged cast member Brent Spiner's 1991 vocal pop album Ol' Yellow Eyes Is Back.

His work on ST: TNG led to McCarthy composing the score for the 1994 feature film Star Trek: Generations, as well as for episodes of Star Trek: Deep Space Nine (1993-1999), Star Trek: Voyager (1995-2001), and Star Trek: Enterprise (2001-2005). His music could also be heard in franchise-related video games and attractions.

In the meantime, McCarthy kept busy with a number of other TV series and films, among them 1996's Utilizer, 1997's McHale's Navy, and the TV series Project Greenlight (2001-2002). Still going strong into the 2010s, he composed music for the 2011 Jason Priestley TV movie Prayer Hour, in addition to several film shorts. ~ Marcy Donelson