That depends on which Maverick you are asking about. There were several:
James Garner - known later for his "Rockford Files" series - started the series as Bret Maverick (a character later played by Mel Gibson in the 1994 movie "Maverick") When it was realized that production time was longer than the network would be happy with, the idea to add another Maverick came to be and so was hired:
Jack Kelly - known for his role in several films including the sci-fi classic "Forbidden Planet" - as Bret's equally skilled and charming brother Bart Maverick. For the first three seasons, Garner and Kelly alternated as leads weekly and on some episodes appeared together. Garner filed a lawsuit against Warner Brothers at the end of the third season (although one episode filmed for season 3 ended up being shown in season 4) which resulted in his leaving the show and being replaced by:
Roger Moore - known later for his series "The Saint" and of course as James Bond - as cousin Beau Maverick. Having 'shamed' the family by receiving a metal for heroism in the Civil War (totally by accident) Beau was sent to England for a few years where he picked up a 'slight' English accent. (No effort to cover Moore's natural accent was even attempted) But near the end of season 4, Moore also left the show due to his dislike of the scripts. That led to the next Maverick:
Robert Colbert - known later for his sci-fi series "The Time Tunnel" - as Brent Maverick, the youngest of the Maverick brothers. He was removed after only two episodes leaving Jack Kelly's Bart Maverick to be the only Maverick during the final season although re-runs of Garner episodes were added to fill out the time.
All totaled the number of episodes played by each actor were:
Jack Kelly - 75
James Garner - 52
Roger Moore - 15
Robert Colbert - 2
As a side bit of trivia, there were a three other Mavericks in the series.
Beauregard "Pappy" Maverick - the often mentioned father of Bret/Bart/Brent, played by Garner under heavy make-up in season 3
Bentley Maverick - brother of Pappy and assumed father of Moore's Cousin Beau, played by Kelly under heavy make-up in season 3
Micca Maverick - not seen, but another brother of Pappy's and the reason Bret and Bart inherate a stage line in season 4's "The Maverick Line" (filmed for season 3.)
James Garner was Bret - Jack Kelly was Bart
Country Style - TV series - ended on 1950-11-25.
None , but he did star in the TV Series "Bronk" [1975-76] & The Greatest Show On Earth [1963] , which only ran for one series.
The 4 corners of the world
Gail Davis played her on television from 1954 to 1956.
James Garner was Bret - Jack Kelly was Bart
Al Barlick has: Played Himself - Left Field Umpire in "1950 World Series" in 1950. Played Himself - Right Field Umpire in "1950 World Series" in 1950. Played Himself - Third Base Umpire in "1951 World Series" in 1951. Played Himself - Home Plate Umpire in "1951 World Series" in 1951. Played Himself - Second Base Umpire in "1951 World Series" in 1951. Played Himself - First Base Umpire. in "1951 World Series" in 1951. Played Home Plate Umpire in "The Odd Couple" in 1968.
Your Witness - TV series - ended in 1950.
The Web - TV series - was created in 1950.
Danger - TV series - was created on 1950-09-19.
Allie Reynolds has: Played Himself - New York Yankees Pitcher in "1947 World Series" in 1947. Played himself in "Toast of the Town" in 1948. Played Himself - New York Yankees Pitcher in "1949 World Series" in 1949. Played himself in "The Arthur Murray Party" in 1950. Played Himself - AL Pitcher in "1950 MLB All-Star Game" in 1950. Played Himself - New York Yankees Pitcher in "1950 World Series" in 1950. Played Himself - New York Yankees Pitcher in "1951 World Series" in 1951. Played Himself - New York Yankees Pitcher in "1952 World Series" in 1952. Played Himself - New York Yankees Pitcher in "1953 World Series" in 1953. Played Himself - AL Pitcher in "1953 MLB All-Star Game" in 1953.
Country Style - TV series - was created on 1950-07-29.
Country Style - TV series - ended on 1950-11-25.
The Cisco Kid - TV series - was created on 1950-09-05.
Which TV series? There have been a lot of TV series worldwide with a lot of songs. You have to name the TV series first. TVs have been around since the 1950's. That's a lot of shows with a lot of songs. Maybe if you went to Google and looked up "Songs associated with TV series" you might have better success if you don't know the name of the TV series.
Comedy
Elmer Davis has: Played Himself - Guest Panelist in "Information Please: Series 1, No. 9" in 1940. Played Narrator in "The Golden Twenties" in 1950. Played Himself - The Stage Manager in "Pulitzer Prize Playhouse" in 1950. Played Himself - Narrator in "Pulitzer Prize Playhouse" in 1950. Played Narrator in "Pulitzer Prize Playhouse" in 1950. Played Himself - Commentator in "The Day the Earth Stood Still" in 1951.