TV Shows since the inception of TV shows have always had music play at the beginning of every episode. The piece of music is called a Theme Song or Opening Titles Song. Many theme songs over the years have been mega hits!
The Brady Bunch theme song is one of those that just gets stuck in your head.
More modern theme songs such as for AMC’s Mad Men feature instrumental cues and less song performances.
The most famous tv theme song of all time is “I’ll be there for you” by Rembrandts from FRIENDS.