Johnson took part in a series of kicking and match simulation drills at Moore Park on Monday, almost 12 months since tearing his anterior cruciate ligament.
The season-ending injury, suffered in the 2013 NAB Cup, required two knee reconstructions in the space of four months.
But the 21-year-old said he was rapt to be back on the training track - partly because of his pairing with superstar recruit Lance Franklin.
"I had a smile on my face for all of the session because I'm feeling really good at the moment," Johnson told the Swans' website.
"I did a few game scenario drills and I did feel a little bit lost out there, but I'm sure it will all come back over the next few weeks.
"To be able to play on (Franklin) in training is really good for me and hopefully I can build from there."
Johnson won't be ready for this month's opening pre-season fixtures against Greater Western Sydney and West Coast, but is hoping to return for the Swans' third practice match versus Brisbane on March 8.
"I've just got to see how I'm pulling up after each session and make sure that the knee is responding pretty well from sessions and that type of thing," he said.
"I had a smile on my face at training, so I just can't imagine the feeling when I'm finally out there playing with the other boys."
Sydney kick off their 2014 campaign against cross-town rivals GWS at Spotless Stadium on March 15.
Meanwhile midfielder Tom Mitchell, who also missed most of 2013 through injury, Franklin and Lewis Jetta have all been named to play in the Swans' intra-club match on Wednesday night.