RWBY had been a long-standing concept of Oum's for years before it began development. Towards the end of his work on the 10th season of Rooster Teeth's Red vs. Blue, he developed the color-coding approach to character names and design as a hook for the series. During production on Red vs. Blue season 10, Oum asked series creator Burnie Burns if they could produce RWBY following the conclusion of that season. Burns, worried for the production schedule, told Oum "If you finish Season 10, then you can do whatever you want." Production on RWBY began as intended, with the first trailer being finished within two weeks and premiering after the credits of the Red vs. Blue season 10 finale on November 5, 2012.
Oum designed the characters with assistance from artist Eileen "Einlee" Chang. The characters utilize designs inspired by classic fairy tale characters. Each character has an associated color, and it is the first letters of these colors, red, white, black, and yellow, that give the series its name. The series is written by Oum, along with fellow Rooster Teeth employees Miles Luna and Kerry Shawcross. Oum was initially concerned about a story focusing on female characters being developed by a primarily male crew, but said they managed to do well developing the female characters. The series is animated by Rooster Teeth's internal animation team using Smith Micro's Poser software. The series' music is composed by Jeff Williams, who previously composed the soundtracks for Seasons 8–10 of Red vs. Blue, and features vocals by Williams' daughter, Casey Lee Williams.
A series of four promotional trailers, one for each lead character, were released in the lead-up to the series premiere. They were primarily produced by Oum and assistant animator Shane Newville. Each trailer begins by unveiling one of the four primary characters and then showing a detailed action sequence. The "Red" trailer was shown after the credits for Red vs. Blue's season 10 finale in November 2012. It was followed by the "White" trailer in February 2013. The "Black" trailer was unveiled at a PAX East panel at the end of March and was the first to include voice-acted dialogue. Following the premiere of the "Black" trailer, Oum noted with regret that the first two trailers were shorter and had less character development. The "Yellow" trailer was shown at Rooster Teeth's A-Kon panel on June 1, 2013. Music from the trailers is being sold for digital download on several online retailers.
The first episode premiered on July 5, 2013, at a panel at RTX 2013. It premiered online two weeks later on July 18, 2013.