Gloucester-Hartpury lock Aldcroft, capped 58 times by England, will skipper the Red Roses in the upcoming Women's Six Nations and the home Rugby World Cup, which starts in August.
The 28-year-old, who succeeds Marlie Packer as skipper, has previously led England on several occasions, with her first match as captain an 89-0 thrashing of the United States in November 2021.
England women's coach John Mitchell hailed Aldcroft as a "phenomenal rugby player", saying: She leads by example through her world-class actions, on and off the field, and is an integral member of our leadership group."
New Zealander Mitchell, a former All Blacks coach, said it was a difficult choice to remove the 35-year-old Packer as captain.
"As with many positions, there is intense competition for places in the back row and Marlie's ability to deliver big performances on the pitch needs to be her focus," he explained.
"Making decisions like this is never easy, but I believe it will push us to perform at our best and ultimately benefit the Red Roses."
Aldcroft was named 2021 World Rugby women's player of the year and led Gloucester-Hartpury to the last two Premiership titles.
"It's an incredible honour to be awarded the Red Roses captaincy," she said.
Saracens flanker Packer captained England to two Six Nations Grand Slams, as well as being crowned 2023 World Rugby women's player of the year.
England went undefeated in 2024 and are favourites for the World Cup, where they hope to avenge agonising defeats by New Zealand in the past two finals.
