Uncertainty shrouds Johnson's future following a highly disappointing World Cup during which the squad were criticised for their performances on the pitch and behaviour off it.
It is unknown whether Johnson wishes to continue as manager or if the Rugby Football Union want him to remain in charge.
Hartley, who was one of three England players warned by Johnson for making inappropriate comments to a female hotel worker while in New Zealand, has pledged his loyalty to the former Lions captain.
"It's not my position to comment on what is going on in board rooms," said the Northampton captain.
"All I can say is that in New Zealand Johnno stuck by me and stuck by the players, so the players will stick by him.
"It wasn't only Johnson in New Zealand. There were 40 other people out there with him and we've got to stick together."
Hartley admits it has been a struggle to acclimatise to life after the World Cup, but insists he has learnt from the events in New Zealand.
"It's just a disappointment. Then there's the comedown," he said.
"It has taken me a couple of weeks to readjust to life and be out of that World Cup circle, and that has been a comedown.
"The wonderful thing is that we get to play every Saturday and you can put things behind you when you play week in, week out.
"As a player, all I can do is play week in and hopefully play well.
"When the chance comes to play for England again then hopefully I can put myself forward for that.
"In all areas I have learnt. It's experience, isn't it?
"You get a year older, you play in a World Cup, another Heineken Cup, another Premiership campaign, you are always going to learn things. I have taken stuff from that."
The 25-year-old, who lost his place as first-choice hooker to Steve Thompson in New Zealand, is cautious over throwing his hat into the ring to replace the retiring Lewis Moody as England captain.
"I've got to play well for my club first. I can't think about anything else," he said.
"I have to focus on getting back within that England set-up.
"There was obvious disappointment both on and off the field and I just want to get back playing well for Saints and hopefully get the chance to play for England again."
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