Justman served as Star Trek's co-producer during the first 14 episodes of its third season before resigning due to his displeasure at the show's decline in production and script quality as well as what he regarded as the show's poor treatment by NBC which had slashed its budget during the third season.[2]
Along with Herbert F. Solow, he wrote Inside Star Trek: The Real Story, published by Pocket Books in 1996. According to Publishers Weekly, "As told by Solow, Star Trek's co-producer [sic], and Justman, the executive in charge of production [sic], this is arguably the definitive history of the TV show...With plenty of behind-the-scenes material that will be of interest to Trek fans, this book puts a good deal of emphasis on the show's business side, elucidating production difficulties, cost overruns and the seemingly constant debate with NBC over the show's future."