The former world No 1 was playing his first official match since retiring during his Wimbledon quarter-final against Tomas Berdych last year with elbow problems that forced him to miss the rest of the season.
When Djokovic pulled out of warm-up tournaments, there were doubts over whether he would be fit enough to play at Melbourne Park, where he shares the record of six titles with Roy Emerson.
He was cautious about his fitness on the eve of the tournament and wore a compression sleeve but there were no signs of rust as he eased to a 6-1 6-2 6-4 victory over American Young.
Djokovic has remodelled his service action with the help of coaches Andre Agassi and Radek Stepanek, shortening the back swing in a bid to protect the elbow, and it held up very well.
He said: “It feels so great to be back here, so great to be back on the tennis court. There’s no better place for me to be playing after six months than here.
“A month ago I didn’t know if I was going to come to Australia or not because the elbow was still not prepared for this level of competition.”
There were even greater doubts over Stan Wawrinka, who has also been sidelined since Wimbledon following knee surgery.
Wawrinka argued neither his game nor his fitness were anywhere near where he would want them to be but he battled to beat Ricardas Berankis 6-3 6-4 2-6 7-6 (7/2).
Fourth seed Alexander Zverev was tested by Thomas Fabbiano but did not drop a set in a 6-1 7-6 (7/5) 7-5 victory but 22nd seed Milos Raonic was beaten 6-7 (5/7) 7-5 6-4 7-6 (7/4) by Lukas Lacko.
David Goffin was a set and a break down against Matthias Bachinger but recovered to win 6-7 (3/7) 6-3 6-2 6-4.