The New Zealander has reinvigorated England's Test set-up alongside captain Ben Stokes since 2022 and will seek to bring his attacking "Bazball" approach to the limited-overs teams.
The 42-year-old has extended his contract until the end of 2027, officially taking over the one-day international and Twenty20 sides in January to coincide with a tour of India and the Champions Trophy in Pakistan.
The England and Wales Cricket Board said the broadened role for McCullum was part of a "strategic restructure" of the men's set-up.
"I believe we are incredibly fortunate that a coach of his quality is prepared to commit wholeheartedly to English cricket," said Rob Key, managing director of England men's cricket.
"Being able to align all teams now is particularly exciting and we look forward to taking on all challenges that come our way.
"For the last two years, constant clashes between formats have made it challenging for the white-ball environment -- fortunately, these are easing starting from January."
McCullum, a former New Zealand captain known for his attacking batting, said he was excited to extend his role with England.
"This new challenge is something I'm ready to embrace, and I'm eager to work closely with (captain) Jos (Buttler) and the team to build on the strong foundations that are already in place," he said.
He added: "The talent within English cricket is immense, and I'm looking forward to helping these players reach their full potential."
'Energised by the prospect'
McCullum inherits a white-ball outfit that have surrendered titles in both limited-overs World Cups in the past 12 months, which led to the departure of former white-ball coach Matthew Mott in July.
England are currently ranked seventh in ODI (50-over) cricket and fourth in the T20 standings.
McCullum will be at the helm as England try to win the trophies back, with the next T20 World Cup in India and Sri Lanka in 2026 and the 50-over equivalent in southern Africa in 2027.
Former England batter Marcus Trescothick will serve as interim head coach for the upcoming white-ball series against Australia at home and the tour of the Caribbean.
When McCullum took charge of England's Test side in May 2022 they were at a low ebb, with just one in 17 games.
But under his leadership they have won 19 of their 28 Tests since and score at a remarkably rapid rate.
The biggest disappointment during his tenure has been a crushing 4-1 defeat in India.
Chris Silverwood's sacking after the 2021/22 Ashes was followed by an acceptance that the unrelenting timetable of international cricket, with some Test and white-ball assignments overlapping, was too much for one head coach.
But with England's fixture programme looking more manageable for the next couple of years, McCullum, who still lives in New Zealand, has agreed to extend his role.
"The idea of a unified coaching structure, especially with the schedule easing next year, made perfect sense," he said.
"I'm energised by the prospect of guiding both teams."
