Each episode usually had two contestants. After that, a celebrity guest played. Once in a while, if there was extra time, the celebrity was followed by a third regular guest.
Each round was a guessing game. The panel tried to figure out the contestants' "secrets". The idea of a "secret" on the show was very broad. Secrets were always intended to be unusual, amazing, embarrassing or humorous. They often were about what happened to a person, owning something, or a job, hobby, success or skill.
One or more contestants would walk on. The host would tell the name the contestant or ask their name and where they were from. He would then ask them to "whisper your secret to me, and we'll show it to the folks at home." The contestant would then whisper their secret to the host, while the audience and television viewers were shown the secret by writing printed on the television screen. Then the host would give the panel a clue. For example, "the secret concerns something that happened to [Contestant's Name]." The host would then choose a panelist to begin asking questions.
When the show first started, each panelist had 15 seconds of questioning of a guest. Then this would repeat once. Each 15 seconds that passed without the secret being correctly guessed won the contestant $10. However, a guest could not win more than $80. In mid-1954, they changed to only one question period for each panelist. They changed the money to $20 so that the top prize would stay at $80. Also, the time limit for questions was no longer exact. Instead, a buzzer went off to end the questioning, and production staff decided when to use the buzzer. This was partly because the program was shown live (not taped), and this sometimes required the show to be longer or shorter to keep the show running on time. In later times, the panelists were sometimes buzzed when they were too close to the secret, or at a point that would get a laugh.
Following the guest's secret being discovered, the host sometimes asked the contestant more about their secret, or, if it made sense, the contestant demonstrated their secret. These demonstrations sometimes included the host, and sometimes one or more of the panelists.
A number of famous people appeared with secrets, including Col. Harland Sanders who founded Kentucky Fried Chicken ("I started my restaurant with my first Social Security check"), Philo T. Farnsworth ("I invented electronic television"), Pete Best ("I used to be one of THE BEATLES"), and an elderly man, Samuel Seymour, who was the last surviving eyewitness to Abraham Lincoln's assassination (he was 5 years old at the time).
On each usual episode, a celebrity guest came on the show with a secret. The celebrity usually started the episode by coming out from the behind the curtain and saying "my name is [Name] and I've Got a Secret!". Sometimes, though, the celebrity would say "and this is "I've Got a Secret"!". In the beginning, the celebrities would have a secret. The secrets would sometimes be personal secrets, similar to the other contestants. Other times the secret would be about something they were there to do. The guest part of the show often was really a was to show some new technology or product.
Later in the show, a common thing was for the celebrity to challenge the panel in some other game. This later became the main use of the celebrity part of the show, and they no longer pretended to have a secret. Instead, the celebrity would just come out with a challenge for the panel. Several of these challenges later were the main idea used for other game shows. For example, a game in which Woody Allen challenged the panel to guess words by what children had said they meant, which became the basis for "Child's Play". Or two challenges with Peter Falk and Soupy Sales in which the panel had to guess who a celebrity was after being show a photographs of them as a baby and others as the aged, which later was used for the show, "Face the Music".
"I've Got a Secret" was more informal than its sister show "What's My Line?". The panel and host used each other's first names. As noted, the time limit on questioning was removed early in the show', and time limits were set more for entertainment. The men on the panel always wore normal suits or even sport jackets, though both Morgan and Moore sometimes chose bow ties over straight ties. Until the later years of the series, both Moore, and members of the panel smoked cigarettes on the air. The panel was introduced at the start of each episode by the host, usually with a pun on their names.
Only yes-or-no questions were supposed to be asked by the panel, but this was often relaxed. Unlike on "What's My Line?", the host offered hints and suggestions when the panel was quite lost, or when an answer might make them lost. Like on "What's My Line?", the panelists were not allowed to try to figure out secrets together, but later in the series, no one bothered the panelists when they whispered ideas to each other.
The series began in black-and-white, and only in 1966 switched to color. When the show is seen in reruns, though even episodes which were in color are in black and white, as they did not "record" the color. Much of the series had a commercial sponsor. The opening of the show would have an advertisement for that company. Signs on the set also promoted the products, and on commercial breaks the product would be advertised. Some sponsors provided samples of their products, which were given to each contestant. Late in the series, sponsorship was stopped.
An Australian version of the show was produced and aired in Brisbane on QTQ Channel 9 from 1967 until 1973. It was hosted by Newsreader Don Secombe. Similar to the American version, it had regular celebrity panelists including Ron Cadee, Babette Stevens and Joy Chambers.
The format of the 1970s revivals were very similar to the original series. However celebrity secrets were back, as opposed to challenges.
On the Oxygen revival, the contestant earned $200, and if no one on the panel guessed, they earned a $1,000 prize. Stephanie Miller hosted this version. The show's set was made to look like a fancy city apartment.
On GSN's revival, each panelist had 40 seconds for questioning, with one conference allowed. Stumping the entire panel won the contestant $1,000 and "dinner for 2 in Beverly Hills." The fine print at the end of the show disclosed that contestants were also paid an appearance fee. Losing contestants also received some unspecified parting gifts. Several minor show business professionals demonstrated their performances on the show, including piano juggler Dan Menendez. Another element in the revival was that all the panelists were openly gay. This was played upon as host, Bill Dwyer, was introduced as "the straight man to the panel".
As with "What's My Line?", early episodes from the original series' first season in 1952 appear to have been lost. From late 1952 until the 1967 cancellation, most episodes appear to exist as a digital transfer of the original black-and-white kinescope movies.
GSN concluded its most recent airing of "I've Got A Secret"'s run on July 13, 2008 at 3:30 AM (ET), paired with "What's My Line?" at 3:00. However, they began their run in mid-2007 with episodes from late 1961 or early 1962. A good portion of the series is unlikely to be aired, due to the show's longtime sponsorship by Winston cigarettes, which remains an existing brand. It is unclear whether this is mandated legally, or simply a choice by GSN. In addition, the network skipped several episodes through its run which are known to have been skipped in previous runs of the show; this may mean that other episodes are lost or in bad enough condition for GSN not to air them.