Captain Wainwright was a member of the United States Army Air Forces in the 1940s. In that capacity, he assisted General Rex Denning in investigating the crash landing of an extraterrestrial spacecraft in Roswell, New Mexico, in July 1947.
Wainwright was responsible for ordering an Air Forces member in Roswell to retract his statement to the press that a spacecraft had been recovered, and issued a statement claiming that they had only recovered a weather balloon. In the meantime, the three alien occupants of the craft, who were actually the Ferengi Quark, Rom, and Nog, who had accidentally traveled back in time via time warp from the year 2372, were kept in an examination room on a military base, while Denning and Wainwright attempted to ascertain the possible national security threat that they posed. Although Quark insisted that they only wanted to make a profit by selling advanced technology from the future to the Humans, Denning and Wainwright remained convinced that they were part of an alien invasion force. Interrogating the three Ferengi, Wainwright attempted to force them to admit to their true intentions, and even threatened them with a scalpel. In response to this, Faith Garland, an Army nurse, and her fiancee, Professor Jeff Carlson, incapacitated Wainwright and helped the Ferengi to escape. The Ferengi subsequently retrieved their shuttle from Hangar 18 on the other side of the base, and were able to return to their own time by recreating the time warp. Afterward, General Denning issued orders that the cover story of a weather balloon-recovery remain intact, and that the public not be made aware of the actual events which had transpired. (DS9: "Little Green Men")