On 29 November 2020, at the age of 16 years and 10 months, Lazetić made his debut for Red Star Belgrade as an 76th-minute substitute for Richmond Boakye against Rad.
[3] On 27 January 2022, five days after his 18th birthday, Lazetić joined Serie A club AC Milan for a fee believed to be in the region of €4 million, signing a deal until June 2026.
[5] He debuted for the first team on 19 April, in a Coppa Italia match against cross-city rivals Inter Milan, coming on as a substitute in the 86th minute.
[10][11] On 18 June 2024, he moved back to his native Serbia and joined Serbian SuperLiga club TSC on a season-long loan.
[13] Red Star Belgrade AC Milan This biographical article related to a Serbian association football forward is a stub.