Johnson's future will become the focus of intense speculation in the coming months, with any number of teams happy to give one of rugby union's biggest names a position on their coaching staff.
The 34-year-old has yet to make any post-retirement plans but has revealed he would like to stay in the game - and refused to rule out the possibility of eventually becoming England boss.
"I've been very fortunate to have enjoyed some great experiences from playing rugby for 16 years, and it would be selfish of me not to pass those on at some point if I'm able to," he told BBC Radio Five Live's Sportsweek programme.
"Whether that will happen on an ad-hoc basis with junior teams or whether it will be full time in the Premiership, I don't know.
"We'll have to see when I have some time off and have had the opportunity to think about it. I'll make a decision then.
"I have no track record as a coach, only as a player. You have to learn your trade. I can't start thinking about England until I've been involved at a lower level.
"But if I took up coaching, enjoyed it and wanted to be the best I could then coaching England would be the ultimate thing to do.
"But right now I have no ambitions to coach anywhere, let alone at international level."
Johnson was widely touted as a possibility for the summer Lions tour to New Zealand, but the Leicester second row - who called time on his England career 12 months ago - insists that was never an option.
He said: "It would be very hard to get picked for the Lions when you're not playing in the Six Nations.
"There's a perception around that some of the guys who played in Sydney in
2003 would turn up for the Lions and everything would fall back into place.
"But that's not the way it works. By the time the Lions tour gets under way it will have been 18 months since I played Test rugby, and that's a long time to be out - especially when you're nearing the end of your career.
"There are plenty of good players around, and it's time for some other guys to get their chance."
Johnson's inspirational leadership for England and the Lions has seen him hailed as his country's greatest captain in any sport.
But he said: "People can get carried away - I don't think I'm anywhere near England's greatest sporting captain.
"If you win games people think you're a great captain. But you need a good team to win games, and I've been lucky enough to be part of a good team.
"I was lucky enough to play in a side which won a World Cup. I think any number of guys could have captained that side to success. I've always said captains get too much credit when things go well."