Mitchell, 59, will replace Simon Middleton, who stood down after eight years at the helm following England's Six Nations Grand Slam triumph at Twickenham on Saturday.
Under Middleton, the Red Roses, the dominant force in the European women's game, won 30 successive matches before losing to hosts New Zealand in last year's World Cup final.
Mitchell, currently the defence coach for the Japan men's team, will take up his England role following October's men's World Cup in France.
Former England captain Sarah Hunter, who retired in May, will join his backroom staff.
Mitchell led his native New Zealand to the semi-finals of the 2003 World Cup and his career has also included a four-year stint as defence coach of the England men's side under former boss Eddie Jones.
