"We have a very good group of players and I'm looking forward to leading them out in the summer, building on Alastair's achievements and making the most of our talents in the years ahead.
"The senior guys in the changing room play a very influential role and whilst there's a natural progression for me it's a huge support to know that they are there to help and advise."
Ben Stokes has been named vice-captain as the new generation of England players takes over formal leadership roles.
Root's promotion has been expected ever since Alastair Cook signalled he could be standing down at the end of the India tour.
Cook was given time to consider his decision as Strauss did not want Root to be distracted by the Test captaincy during the one day series in India. Cook stood down last Monday, just a couple of days after the one-day team returned.
Strauss met with Root last Thursday along with James Whitaker, the chairman of selectors, and spoke on a conference call with Trevor Bayliss, the England coach, who is at home in Australia.