England Test coach Brendon McCullum will also take control of the white-ball teams, the England and Wales Cricket Board announced on Tuesday.
The ECB said the New Zealander would be in charge of both the Test and limited-overs teams from January 2025, coinciding with England's limited-overs tour of India and the ICC Champions Trophy.
"I'm delighted that Brendon has chosen to do both roles now with England," said Rob Key, managing director of England men's cricket.
"I believe we are incredibly fortunate that a coach of his quality is prepared to commit wholeheartedly to English cricket."
The relentless international schedule has made it difficult for one person to take on both roles, with matches in the shorter and longer formats occasionally overlapping.
McCullum and the England and Wales Cricket Board (ECB), which has extended his contract until 2027, believe it is now possible because of changes to the calendar.
"The idea of a unified coaching structure, especially with the schedule easing next year, made perfect sense," McCullum said.
"I'm energised by the prospect of guiding both teams and am grateful for the support from the ECB and my family as I take on these added responsibilities," the former Blackcaps skipper added.
The ECB's decision comes after Matthew Mott resigned as the three lions' white-ball coach on July 30 after presiding over the team's disappointing defences of its ODI and T20 world titles.
Mott was in charge for two years and led England to the T20 World Cup title in 2022, but was no longer getting the best out of a talented group captained by Jos Buttler, whose position also came under scrutiny.
Rob Key decided a "new direction" was needed, so enter McCullum, the laid-back Kiwi whose 'Bazball' approach, as it has been widely labelled, has led to an improvement in the fortunes of England's test team under captain Ben Stokes.
Essentially, it gives players licence to be more attacking and emboldened with their shot-making and field placings, and be free from recrimination.
"The talent within English cricket is immense, and I'm looking forward to helping these players reach their full potential," McCullum said.
"My goal is to create an environment where everyone can thrive and where we can continue to compete at the highest level across all formats."
McCullum will start his dual roles in January, coinciding with England's white-ball tour of India and the Champions Trophy.
In the interim, Marcus Trescothick will serve as coach for the upcoming white-ball series against Australia and the tour of the Caribbean.
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.
The timing of the schedule (from January) will allow him to dedicate the necessary focus to both roles, and we're confident this restructure will bring out the best in our players and coaching staff.
The English held both white-ball world titles after winning the 50-over crown in 2019 and the T20 crown three years later.
They surrendered the 50-over title last year in dismal fashion after losing six of their nine group games in India.
England was then thrashed in the semifinals of the T20 World Cup by eventual champion India in June.