Iosefo grew up in Wahiawa on the island of Oahu in Hawaii where he learned to play rugby.
[2] After finishing Leilehua High School in Wahiawa, he went to the University of Montana to play wide receiver in American football as a walk-on.
Iosefo also played for the U.S. at the 2015 NACRA Sevens where the United States beat Canada in the final 21–5 to qualify for the 2016 Summer Olympics.
[11] At the 2016 London Sevens, Iosefo scored a try 11 seconds into the match against Fiji, one of the fastest tries in the World Series.
As of the end of 2021, Iosefo was ranked among the top U.S. players for statistics on the World Rugby Sevens Series: