Beauvillier played three seasons with Shawinigan of the Quebec Major Junior Hockey League and was captain for Team Cherry in the 2015 CHL/NHL Top Prospects Game. He was selected by the Islanders in the first round (No. 28) of the 2015 NHL Draft.

Beauvillier made the Islanders roster as a 19-year-old and scored his first NHL goal Oct. 18, 2016, against the San Jose Sharks at Barclays Center.

An alternate captain for Team Quebec at the 2014 World Under-17 Hockey Challenge, Beauvillier has also represented Canada at several international events and helped it win the gold medal at the 2015 Ivan Hlinka Memorial Cup and the bronze at the 2015 World Under-18 Championship.