Upon his return to Detroit, McCarthy hosted the Morning Music Hall from 6:15 to 9 and the Afternoon Music Hall from 3:15 to 6. Eventually, McCarthy's duties were changed to morning drive, and a noontime interview program, "Focus". It wasn't long before McCarthy's morning show was #1 in Detroit, a position that he held for about 30 years until his death, a feat unmatched in Detroit radio. McCarthy divorced upon his return to Detroit and soon after met Judy Buttorf, who worked at
General Motors headquarters, which at the time were across the street from the
Fisher Building where the WJR studios are located. They married in 1965 and stayed together until McCarthy's death. They had one son together, James (Jamie). McCarthy's morning show included a mix of music, news, and sports, but his greatest fame was as an interviewer (both on his morning show, and on "Focus"). One morning during the 1992 presidential election, he interviewed President
George H. W. Bush and candidates
Bill Clinton and
Ross Perot all within one hour.
Dick Vitale – whom McCarthy was the first to christen "Dicky Vee" – was a regular and friend of the program. Eventually, the music component of the show would be phased out so McCarthy would have more time to concentrate on the news of the day or any topic that would interest him. Former producer Hal Youngblood once said "Everyone is interested in what J. P. is interested in because he makes them interested in it." His curiosity ranged between business, current events, history, entertainment, and other topics. McCarthy had a great love for sports, especially the
Detroit Tigers. He interviewed Tiger managers
Billy Martin,
Ralph Houk and
Sparky Anderson on his shows daily during the baseball season. In 1975, he served as a
color commentator on WJR's
Detroit Lions broadcasts. McCarthy occasionally had dialogue with a series of characters created by his friend Robert "Fat Bob" Taylor. Taylor, an aspiring
opera singer who earned a living as a
plumber, first appeared on the "Focus" show in 1966. Over the years, he developed characters like "Luigi at the Car Wash", and "Mrs. Pennyfeather" (a witty elderly woman). "
Grosse Pointe Charles" (a snooty aristocrat), was generally believed to be Taylor, but, according to JPMcCarthy.net, was a real person from one of the "Pointes". Taylor would eventually host his own weekend show on WJR and the morning show at
WAAM in
Ann Arbor. He died in June 1995. McCarthy thrived on call-ins, which were rarely screened, with features like "The Answer Man", where he answered callers' questions in a comical voice, "Winners and Losers Of The Day", where callers would nominate local newsmakers for the winner or loser of the day, and "What's Bothering You?", where callers would gripe about what was in the news or issues like rudeness or unscrupulous businesses. But, most popularly, McCarthy would take calls from Detroit executives and celebrities who were his friends. McCarthy also was known for the stock phrases he would intersperse into his radio show. He opened every show at 6:15 a.m. with the greeting to listeners, "Good mornin' world," and his phrases "They're playing golf somewhere," "It's not the money, it's the amount," "It's brass monkey weather," and "Remember my name in
Cheboygan – just don't tell 'em where I am," were only a few that endeared him to his listeners. ==Hobbies and interests==