Jenkins decommitted in the moments following James Franklin's firing.
Smith is in his 12th season as a coach at Penn State.
Franklin went 104-45 at Penn State and is tied with the second-most wins by a head coach in program history.
With Drew Allar's Penn State career over, it's Grunkemeyer's turn at the helm for the Nittany Lions.
Penn State sits amongst the bottom four of the Big Ten standings after going 0-3 in its first three conference games.
The Franklin era has to end.