The edge rusher will play at Penn State for his fifth and final year of eligibility.
Carter is the 28th Nittany Lion to be inducted into the College Football Hall of Fame.
Nagao was ranked as high as No. 7 in the country at 141 pounds this season.
Grunkemeyer impressed in seven starts after taking over for an injured Drew Allar.
Landry is the latest coach to follow Matt Campbell from Iowa State.
Walker was Penn State's assistant running backs coach for the last four seasons.