[5] He was the son of William Polk Gray (1845–1929), a prominent steamboat captain in the Northwestern United States, and Oceana Falkland Bush.

[1][2][10] On May 4, Gray set an unofficial record for highest altitude reached by a human being, as he attained 42,470 ft (12.94 km) in a balloon over Belleville.

Because of the rapid descent of the balloon, Gray parachuted out at 8,000 feet (2,400 m), disqualifying him from recognition by the Fédération Aéronautique Internationale (FAI), which required that the balloonist land with his craft.

[4] Between 30,000 feet (9,100 m) and 34,000 ft (10.4 km) Gray threw over an empty oxygen cylinder for ballast, and the canister snapped his radio antenna, cutting him off from the ground.

His final journal entry read “Sky deep blue, sun very bright, sand all gone.”[1] His dead body was found in the balloon basket in a tree near Sparta, Tennessee, the next day.

[1] The Scott Field board of inquiry which investigated Gray's death concluded that he died because his clock stopped, causing him to lose track of his time on oxygen and exhaust his supply.