"It's a huge boost to have him back in and playing for us and with his captaincy," Johnson told reporters on Monday.
"And it shows how strong he has been over the last couple of weeks with the tragedy we have had.
"He is a strong leader and has always been an aggressive leader ... he just has something about him when he's out there as captain."
A number of tributes, including players wearing Hughes's Baggy Green cap number of 408 on their shirts, are planned for the opening day at Hughes's adopted home ground.
Johnson said the 25-year-old batsman remains in the forefront of the players' minds but it will not affect his approach to bowling.
"It's going to be an emotional morning ... for me going out there bowling, the first spell might be the most difficult," Johnson said.
He is a strong leader and has always been an aggressive leader ... he just has something about him when he's out there as captain.
Mitchell Johnson
"We have got to play the way we have been playing and that has been aggressive ... if that is bowling the short ball like we have been, then that will be what we do," Johnson added.
"The vibe is good, everyone is keen to get out there and play some cricket now.
"We have got to wait and see how we feel when we get out there, everybody will feel a little bit different." Phillip Hughes honoured by being named 13th man
Young seamer Josh Hazlewood will be 12th man for the first Test, while Hughes has been named honorary 13th man.
Shaun Marsh, called into the 13-man squad as cover for Clarke, misses out and will return to Sheffield Shield cricket with Western Australia.
Barring injury, Marsh will not play the second game at the **ba either with Cricket Australia set to take the same 12 players to Brisbane. PHOTO: Shane Watson (left) and Michael Clarke celebrate winning the fourth Ashes Test at the MCG(Getty Images: Robert Prezioso)
Earlier on Monday, all-rounder Shane Watson tipped Clarke to stand tall and score a hundred in honour of Hughes.
Clarke won praise for his composure since the sudden death of his "little brother", fronting the media on behalf of the Hughes family and later his team-mates, before delivering a touching eulogy at his Macksville funeral last week.
But as attention turned to the first Test in Adelaide, Watson said the captain was ready to play.
"Michael was running around the field with no problems yesterday," Watson told the Nine Network.
"There'll be no doubt that he'll be ready to go in such an emotional Test match. Hughes honoured during Adelaide Test
Hughes named 13th man for Australian team
Australian players to wear number 408 on their shirts
All players to wear black armbands
Pre-match video tribute narrated by Richie Benaud
63 seconds applause to be held before start of play
"I'd be extremely surprised if he didn't peel off another hundred because he's certainly got a lot to play for, as we all do."
Watson, who on Sunday admitted the team was battling some demons, praised his skipper's constant support for Hughes family and strength in the face of such severe personal loss.
Meanwhile, coach Darren Lehmann appeared to confirm the 33-year-old was back in playing form despite the unpredictable nature of his hamstring injury.
"He's done a couple of behind closed doors sessions and then obviously the main session, and got through all that," he told Sky Sports Radio.
"We're pretty confident he'll get through." ABC/AAP
PHOTO: Ready to go ... Michael Clarke speaks to chairman of selectors Rod Marsh (left) and coach Darren Lehmann (right) at the Adelaide Oval.(Getty Images: Ryan Pierse)
PHOTO: Shane Watson (left) and Michael Clarke celebrate winning the fourth Ashes Test at the MCG(Getty Images: Robert Prezioso)
