Matyas played with the United States national rugby sevens team under head coach Matt Hawkins. He earned a full-time contract for the 2013–14 season, playing in six tournaments in the 2013–14 IRB Sevens World Series.[1] After the season, the U.S. brought in a new head coach, Mike Friday, and Matyas's contract with the U.S. sevens team was not renewed for the 2014–15 season.
Matyas debuted for the U.S. national rugby fifteens team on February 20, 2016, at the 2016 Americas Rugby Championship, coming on as a substitute against Chile. Matyas scored his first try for the U.S. on February 18, 2017 against Canada at the 2017 Americas Rugby Championship.[2] Matyas played for the U.S. during the summer 2017 matches against Canada, where U.S. victory qualified the team for the 2019 Rugby World Cup.