Bäckström reached and surpassed 600 assists in a 23 October 2018 game against the Vancouver Canucks, and became the 87th player in NHL history to reach this mark. A pre-game ceremony was held for Bäckström for reaching 600 career assists on 7 November 2018, before the Capitals' game against the Pittsburgh Penguins. In a 4–1 win against the New York Islanders on 26 November, Bäckström recorded three assists and moved to the second place on the Capitals' all-time points list, passing Peter Bondra. In his next game, on 30 November, versus the New Jersey Devils, Bäckström scored his second career regular season hat-trick. On 11 December, Bäckström had his 12th career four-assist game in a 6–2 win over the Detroit Red Wings, tying him with Gilbert Perreault for eighth in NHL history.