Buttler relinquished his duties as ODI and T20I skipper after a disappointing Champions Trophy tournament, which saw England knocked out in the group stage after losing all three of their matches.
The 26-year-old Brook will start his official captaincy duties at the end of May with a home series against West Indies that will feature three ODIs and three T20Is.
Brook said: "It's a real honour to be named England's white-ball captain. Ever since I was a kid playing cricket at Burley in Wharfedale, I dreamed of representing Yorkshire, playing for England, and maybe one day leading the team. To now be given that chance means a great deal to me.
"I want to thank my family and coaches who've supported me every step of the way. Their belief in me has made all the difference and I wouldn't be in this position without them.
"There's so much talent in this country, and I'm looking forward to getting started, moving us forward, and working towards winning series, World Cups and major events.
"I'm excited to get going and give it everything I've got."
Brook has been a key part of England's white-ball set-up since making his debut in January 2022 and has spent the past year as vice-captain in both the ODI and T20 formats.
He has so far played 26 ODIs for England, scoring 816 runs at an average of 34.00, with a top score of 110. In T20 internationals, he has earned 44 caps and a highest score of 81 and was part of the team that won the T20 World Cup in 2022.
Rob Key, managing director of England men's cricket, said: "I'm delighted that Harry Brook has accepted the role as England's white-ball captain across both formats.
"He's been part of our succession planning for some time, albeit this opportunity has come slightly earlier than expected.
"Harry is not only an outstanding cricketer, but also has an excellent cricketing brain and a clear vision for both teams that will help drive us towards winning more series, World Cups and major global tournaments."
Captain Ben Stokes is "very confident" he can fulfill his role as an all-rounder in England's Test team ahead of a busy home schedule as he returns from hamstring surgery.
England have confirmed that New Zealand legend Tim Southee has joined the coaching staff as a 'specialist skills consultant'.
Gujarat Titans batsman Jos Buttler is set to miss the rest of the IPL 2025 season following his selection for England's upcoming series against the West Indies.
Liam Dawson is set to play his first T20I for almost three years after being selected in England's squad for the white-ball series against West Indies that starts later this month.
