On February 24, 2024, as a sophomore, he set a unofficial world indoor record in the 400 m of 44.49 at the SEC Championships held in Fayetteville.

[6] Morales-Williams was the number one sprinter in his age group, training under coach Tony Sharpe with the Speed Academy Athletics Club.

Representing St. Elizabeth, he won OFSAA freshman titles in the 200 and 400 metres, breaking the Canadian U16 record in the latter with 49.14 seconds.

After winning the 400 metres at the SPIRE Scholastic Showcase, he was named MileSplit's National Boys Performer of the Week, the first Canadian to do so.

Outdoors, Morales-Williams lowered his 400 metre personal best to 45.87 seconds at the SEC Championships, though he failed to make the final again.

Despite still being a U20 athlete, Morales-Williams entered in the senior 400 metres at the 2023 Canadian Track and Field Championships, and he went on to win in a personal best of 45.48 seconds.

He was named to the national team for the 2023 Pan American U20 Athletics Championships, where he won a silver medal behind countryman Will Floyd.

In his season opener at the Clemson Invitational, he broke the Canadian record in the indoor 300 metres; 4 weeks later, on the same track, he broke the Canadian record in the indoor 400 metres as well, running a time of 45.39 seconds, over 2 seconds faster than his personal best from the previous year and even faster than his outdoor personal best.

He broke Kerron Clement's world official record of 44.57,[4] and ran faster than Michael Norman's unratified mark of 44.52, who was also coached by Gilbert.