Mac Allister, like his two brothers, started his career with
Argentinos Juniors. Mac Allister's debut for the club came on 15 May 2016 in an
Argentine Primera División draw with
Lanús. His first appearance for Boca was in a 0–0 with
Flandria on 8 October, prior to scoring his first goal in November versus
Independiente Rivadavia. In June 2022, Mac Allister moved to fellow league club
Rosario Central. In February 2026, Mac Allister moved abroad and signed with Chilean club
Deportes La Serena. ==Personal life==