Courageous Sydney defender Alex Johnson has taken the most significant step in his extraordinary journey back from a fifth knee reconstruction after getting through a NEAFL hit-out on Saturday.

Johnson, who lined up on the grandstand wing and was given a rousing reception by the small crowd at UNSW Canberra Oval, was mobbed by his 17 teammates when he slotted a goal on the run in the second term.

The 25-year-old played the first half of the Swans' massive win over the Canberra Demons and gathered eight possessions, 1,736 days after he ruptured the anterior cruciate ligament in his left knee during a pre-season game against Gold Coast in 2013.

Serious infections have caused Johnson to undergo five ACL reconstructions and 12 surgeries in total since.

The last senior game he played was the 2012 Grand Final triumph over Hawthorn.

Johnson told AFL.com.au he was ecstatic to get back on the park.

"I was alright right up until Friday night when I started thinking about the game and getting nervous," he said.

"I had to work out a pre-game routine because I haven't done it for so long, so I didn't really know how to go about it, but I kept it pretty simple.

"I knew what I wanted to get out of the game, for the first 5-6 minutes I didn't know what I was doing, but just being out there and running around is what I've missed so much, and I'm just to be back playing footy."

Johnson's teammates Lance Franklin, Dan Hannebery, Dane Rampe, Jake Lloyd, Tom Papley, Dean Towers and Nic Newman flew in from Melbourne after their 35-point win over Melbourne at the MCG to show their support.

"I knew a few of the guys were going to come but it's a huge effort to get on the plane early in the morning," he said.

"I'm really grateful for that and I'll be forever grateful for all the support I've had over the whole journey."

With the major milestone of playing a competitive match now ticked off, Johnson will now get to work with the Swans' medical staff, and strength and conditioning team, to make sure he keeps progressing this season.

"We'll just look to increase my game time next week and just get back into the groove of footy again," he said.

"I'm just rapt to have that first one out of the way now and we'll build from there."