Wilson had a career year during the 2017–18 season, putting up career numbers in goals, assists and points. On December 6, 2017, he scored four points in one game for the first time in his NHL career. He scored two goals and two assists to help the Capitals defeat the Chicago Blackhawks. He frequently played on the Capitals' top line with Alexander Ovechkin, and reached double digits in goals for the first time in his NHL career during a game against the Backhawks, to help push the Capitals to the 2018 playoffs. In the playoffs, Wilson was investigated three times by the NHL Department of Player Safety for hits to the heads of opponents that resulted in injury. Wilson's successful season ended with the Capitals winning the Stanley Cup for the first time in franchise history.

This official NHL Washington Capitals puck was signed in silver by Wilson and includes a Fanatics hologram.