Updated: September 30, 2025

In April 1964, Roddenberry presented the Star Trek draft to Desilu Productions, a leading independent television production company. He met with Herbert F. Solow, Desilu's director of production. Solow saw promise in the idea and signed a three-year program-development contract with Roddenberry. Lucille Ball, head of Desilu, was not familiar with the nature of the project, but she was instrumental in getting the pilot produced.

The concept was extensively revised and fleshed out during this time "The Cage" pilot filmed in late 1964 differs in many respects from the March 1964 treatment. Solow, for example, added the "stardate" concept. Desilu Productions had a first-look deal with CBS. Oscar Katz, Desilu's Vice President of Production, went with Roddenberry to pitch the series to the network. They refused to purchase the show, as they already had a similar program in development, the 1965 Irwin Allen series Lost in Space.

In May 1964, Solow, who had previously worked at NBC, met with Grant Tinker, then head of the network's West Coast programming department. Tinker commissioned the first pilot which became "The Cage". NBC turned down the resulting pilot, stating that it was "too cerebral". However, the NBC executives were still impressed with the concept, and they understood that its perceived faults had been partly due to the script that they had selected themselves.

NBC made the unusual decision to pay for a second pilot, using the script called "Where No Man Has Gone Before". Only the character of Spock, played by Leonard Nimoy, was retained from the first pilot, and only two cast members, Majel Barrett and Nimoy, were carried forward into the series. This second pilot proved to be satisfactory to NBC, and the network selected Star Trek to be in its upcoming television schedule for the fall of 1966.

The second pilot introduced most of the other main characters: Captain Kirk ( William Shatner ), Chief Engineer Lt. Commander Scott ( James Doohan ) and Lt. Sulu ( George Takei ), who served as a physicist on the ship in the second pilot, but subsequently became a helmsman throughout the rest of the series. Paul Fix played Dr. Mark Piper in the second pilot; ship's doctor Leonard McCoy ( DeForest Kelley ) joined the cast when filming began for the first season, and he remained for the rest of the series, achieving billing as the third star of the series. Also joining the ship's permanent crew during the first season were the communications officer, Lt. Nyota Uhura ( Nichelle Nichols ), the first African-American woman to hold such an important role in an American television series; the captain's yeoman, Janice Rand ( Grace Lee Whitney ), who departed midway through the first season; and Christine Chapel ( Majel Barrett ), the ship's nurse and assistant to McCoy. Walter Koenig joined the cast as Ensign Pavel Chekov in the series second season.

In February 1966, before the first episode was aired, Star Trek was nearly canceled by Desilu Productions. Desilu had gone from making just one half-hour show ( The Lucy Show ) to deficit-financing a portion of two expensive hour-long shows, Mission: Impossible and Star Trek. Solow was able to convince Lucille Ball that both shows should continue.