Following the crash-landing of an extraterrestrial spacecraft in Roswell, New Mexico in July 1947, U.S. President Harry S. Truman ordered General Denning to find out all that he could from its Ferengi occupants Quark, Rom and Nog. He was unaware that the three aliens had been accidentally sent back in time from 2372. Denning was deeply suspicious of the Ferengi, whom he consistently referred to as "Martians," and believed that they were planning to invade Earth. His subordinate Captain James Wainwright agreed with this assessment of the ersatz Martians. The Ferengi were kept in the Roswell Army Air Field while their vessel was stored in Hangar 18 of the facility.
He smoked cigars. Quark advised him to quit for the good of his health.
Seeking to create a new and better alternate timeline in which the Ferengi would be much more powerful and influential than in the original one, Quark attempted to open up trade for advanced technology with the United States government by negotiating with Denning. However, these attempts caused Denning to distrust Quark even more as his behaviour reminded him of his brother-in-law, a used car salesman. He was also concerned that Quark would make good on his idle threat to supply technology to the Soviet Union if the US government was unwilling to trade.
After reporting back to President Truman, General Denning had the Ferengi detained for interrogation and ordered Wainwright to discover their true purpose in visiting Earth. However, Quark, Rom and Nog were able to escape with the assistance of Professor Jeffrey Carlson and his fiancér Nurse Faith Garland. While Denning and several MPs nearly apprehended the Ferengi, they were incapacitated by Constable Odo, who had stowed away on Quark's ship. The four time travelers returned to their own time by recreating the time warp. Denning then told Captain Wainwright that they had nothing to worry about as they had found nothing more than a crashed weather balloon. (DS9 episode: "Little Green Men")
With the signing of the National Security Act into law by President Harry S. Truman in September of that year, he became a member of the United States Air Force, as did every other serving member of the Army Air Corps. (TOS novel: From History's Shadow)
The unofficial Human-Ferengi first contact became known as the Roswell Incident. Despite the US government's continued assertions to the contrary, rumors that an alien spacecraft crashed in Roswell persisted into the 21st century. Official first contact between humanity and the Ferengi would not take place until 2364, 417 years later. (TOS - Strange New Worlds VI short story: "Whales Weep Not", TOS - The Eugenics Wars novel: The Rise and Fall of Khan Noonien Singh, Volume 2, TNG episode: "The Last Outpost")