The hooker will take charge of the team for the first time against Scotland at Broadwood Stadium, Glasgow on Friday.
Walker, who became the youngest player to captain Carnegie at the age of 18 last year, said: “It is a huge honour just to play for your country.
“So, to lead such a talented bunch of men onto the pitch is a huge privilege.
“I cannot wait for the occasion now and the game itself.”
Walker is one of four Carnegie players named with scrum-half Max Green and openside flanker Josh Bainbridge starting and winger Taylor Prell on the bench.
Walker will hope to follow in the footsteps of elder brother and club-mate Chris, who led England Under-20s to Six Nations glory in 2012.
It was against Scotland two years ago that Walker - then aged only 17 - became the second youngest player, behind only Luke Cowan-Dickie, to make his Under-20s debut.