[2] In 2018 he took part in the Junior International Tournament (JIT), in Lissone, Italy, leading Team Ohio to the win of its fifth title.

[7] Hayes made his NBA debut for the Pelicans on October 10, 2019, scoring 19 points on 8-of-11 shooting against the Golden State Warriors in an 11-point loss.

[8] On November 17, he made his first career start in place of the injured Derrick Favors, achieving his first double-double with 10 points and 10 rebounds along with 3 blocks in a 108–100 victory over the Golden State Warriors.

[9] On January 9, 2020, Hayes recorded his second NBA double-double, scoring 14 points and adding 12 rebounds to go along with 4 blocks in under 24 minutes of play.

[10] Days later, Hayes recorded 18 points and 10 rebounds in a victory over the New York Knicks, tallying consecutive double-doubles for the first time in his NBA career.

[17] He again scored 23 points, alongside twelve rebounds, on April 5, 2022, during a 123–109 win over the Sacramento Kings that helped the Pelicans clinch a play-in tournament spot.

[19] The Pelicans qualified for their first playoff appearance since 2018 after play-in wins over the San Antonio Spurs and Los Angeles Clippers.

On April 22, 2022, during a 111–114 game 3 loss, Hayes was ejected after receiving a flagrant 2 foul for pushing Suns forward Jae Crowder.