The first show to air in a late night time slot itself, Broadway Open House, aired on NBC in 1950 and ended a year later after host Jerry Lester left the show, infuriated at being upstaged by his sidekick Virginia "Dagmar" Lewis.
(As it was, there were also not yet enough television sets in the United States to make television broadcasting in late-night viable; Lester himself was a last-minute replacement host for up-and-coming 26-year-old comic Don Hornsby, who caught polio and died less than a week before the show began.) The first version of The Tonight Show, Tonight Starring Steve Allen, debuted in 1954 on NBC.
Early television variety shows included The Ed Sullivan Show (originally known as Toast of the Town), which aired on CBS Sunday nights from 1948 to 1971 and was hosted by Ed Sullivan, and Texaco Star Theater with Milton Berle, which aired on NBC from 1948 to 1956.
These shows aired once a week in evening time slots that would come to be known as prime time.
Shows that loosely resemble the format air in other countries, but generally air weekly as opposed to the nightly airings of those in the United States.
They also generally air in time slots considered to be prime time in the United States.
By this point, the Federal Communications Commission had lifted a freeze on new television stations, which allowed new stations to pop up across the country, and television adoption soon grew exponentially.
The show was not popular leading to many NBC affiliates dropping the show.
The show returned to the original format that year and was renamed Tonight Starring Jack Paar, with Jack Paar assuming hosting duties.
CBS went without late-night TV until 1969, when it acquired The Merv Griffin Show from syndication; Griffin returned to syndication in 1972, and CBS would not air any further late-night talk shows until 1989, instead opting for reruns, lifestyle programs and imported Canadian dramas in the time slot.
By the 1960s, NBC had already cornered the market for late-night television viewing and would go on to dominate the ratings for several decades.The late-night talk show format was popularized, though not invented, by Johnny Carson with The Tonight Show Starring Johnny Carson on NBC.