The 34-year-old, Brazil's all-time leading scorer, comes back following a prolonged absence due to a series of injuries that kept him out for much of the qualifying campaign, as the five-time champions pursue a record-extending sixth title.
As dozens of journalists gathered at Rio de Janeiro's Museum of Tomorrow for a ceremony featuring music acts and celebrity guests, all eyes were on Ancelotti's decision on whether to include Neymar in the squad.
The 66-year-old Italian, who took charge of Brazil's men's national team last year, had not previously called up the former Barcelona and PSG player. He told Reuters earlier this month that Neymar's inclusion would be based on fitness and form, not sentiment.
"We evaluated Neymar throughout the year and noticed that recently he has been playing consistently and has improved his physical condition," Ancelotti said at a press conference on Monday.
"He has the same role and responsibilities as everyone else, but he is an experienced player. It's true that in some positions we prioritised experience."
Neymar, who has 79 international goals but has not featured for Brazil since 2023, has faced questions about his fitness and form following an injury-marred spell at Al Hilal and an underwhelming return to his boyhood club Santos last year.
The forward said on Sunday he was satisfied he had done all he could to prove he was fully fit and deserved a place in the squad.
"Physically, I feel great. I've been improving with every game," he told reporters after Santos' 3-0 defeat to Coritiba.
The rest of Brazil's squad was largely retained from the qualifying campaign and recent friendlies, with the likes of Vinicius Junior, Raphinha, Matheus Cunha and Endrick shouldering attacking duties alongside Neymar.
Real Madrid striker Rodrygo, defender Eder Militao and Chelsea winger Estevao were left out due to injuries. Chelsea's forward Joao Pedro, midfielder Andrey Santos - who had been called up on previous occasions - also surprisingly missed the final squad. Real Betis winger Antony was also overlooked.
"Some of the players who were with us this year won't be happy with this list. I'm sorry, and I want to thank everyone who was with us," Ancelotti said.
Brazil will open their World Cup campaign against Morocco on June 13th in New Jersey. They also face Haiti and Scotland in Group C.
Brazil's 2026 World Cup squad:
Goalkeepers: Alisson (Liverpool), Ederson (Fenerbahce), Weverton (Gremio)
Defenders: Alex Sandro (Flamengo), Danilo (Flamengo), Leo Pereira (Flamengo), Bremer (Juventus), Douglas Santos (Zenit St Petersburg), Gabriel Magalhaes (Arsenal), Ibanez (Al-Ahli), Marquinhos (Paris Saint-Germain), Wesley (Roma)
Midfielders Bruno Guimaraes (Newcastle), Casemiro (Manchester United), Danilo (Botafogo), Fabinho (Al-Ittihad), Lucas Paqueta (Flamengo).
Forwards: Endrick (Lyon), Gabriel Martinelli (Arsenal), Igor Thiago (Brentford), Luiz Henrique (Zenit), Matheus Cunha (Manchester United), Neymar (Santos), Raphinha (Barcelona), Rayan (Bournemouth), Vinicius Junior (Real Madrid)
