Johnson's future as coach has come under scrutiny following England's quarter-final exit from the World Cup to France on Saturday afternoon.
Director of elite rugby at the RFU Rob Andrew has promised a "robust review" of the whole campaign, though Youngs has insisted that the current national team manager should remain in the position.
"Johnno is definitely the man for the job," he said after returning home from New Zealand earlier today. "Hopefully the RFU will keep hold of him.
"He'll come back a better coach for it and hopefully this squad can start to build from here. If this is the lowest it's going to go, then hopefully we can build from here."
Youngs, 22, played in all five of England's matches at the World Cup.