The Brazilian Football Confederation published a video confirming the deal on Thursday, with Ancelotti speaking directly to supporters about the commitment.
"From the very first minute, I understood what football means to this country. For the past year, we have been working to lead the Brazilian national team back to the very top of the world stage.
"But the CBF and I want more. More victories, more time, more work. We are very happy to announce that we will continue together for another four years. I want to thank the CBF for their trust."
Ancelotti, 66, became the first foreign head coach in Brazil's history when he took the role in May 2025, replacing Dorival Júnior following a turbulent qualification campaign. He oversaw the final stages of South American qualifying, ensuring Brazil reached the tournament, and has since recorded five wins, two draws and three defeats in ten matches.
CBF president Samir Xaud described the announcement as a historic moment.
"This is a historic day for the CBF and for Brazilian football. Another firm step in our commitment to offering the five-time world champion national team an increasingly strong, modern and competitive structure as we work daily to keep Brazil at the highest level of world football."
Ancelotti will name his 26-man World Cup squad on Monday 18 May. Brazil open their Group C campaign against Morocco on 13 June, with further group games against Haiti and Scotland.
His remit beyond the 2026 tournament will include the 2028 Copa América and the 2030 World Cup, which will be co-hosted primarily by Spain, Portugal and Morocco.