Travis Clayton, an English rugby union winger playing in the eighth tier of domestic rugby, was selected by the Buffalo Bills in the final round of the NFL Draft.
The 23-year-old was the 221st overall pick in the seventh round in Detroit.
Clayton, who has never played American football competitively, is expected to play as an offensive lineman.
His club, Basingstoke, play in the Counties 2 Hampshire division, although he has not featured since March 2023.
“With rugby also being a team sport, I believe that helps tremendously,” Clayton said.
“More importantly, playing the wing in rugby helps with the physicality side and with agility.”
Basingstoke coach Richard Cheetham said Clayton’s transition has been “extraordinary” to witness.
“All the players and the coaches would say he’s a gentle giant,” Cheetham told BBC South News.
“He doesn’t have that ferocity in his personality off the pitch, but on it has has all those attributes.”
Clayton, who is 6ft 7in, was selected from the NFL’s International Player Pathway programme, which attempts to find players from outside the United States who are suitable for the sport.
He completed the 40-yard dash in 4.79 seconds during the NFL Combine, an event that collects data from players before the draft.
The Bills said Clayton’s dash was the fastest they had recorded from an offensive lineman in the past 10 years.
In March former Wales rugby union star Louis Rees-Zammit joined Super Bowl champions the Kansas City Chiefs.
This year, for the first time, all 32 NFL franchises will be given an additional place in their practice squads specifically for international players, including those who have come through the pathway programme.
Teams who have an international player in their practice squad will also be allowed to promote them to their active roster, up to three times during the season.