The 12-times Grand Slam winner, seeded an unfamiliar 14, was too strong for American Donald Young, winning 6-1, 6-2, 6-4 in 1hr 51min on Margaret Court Arena.
The Serbian former world number one has been out of action for six months.
But he looked in good fettle as he worked his way into the second round where he will play Frenchman Gael Monfils.
Djokovic, wearing a flesh-coloured protective guard on his right serving elbow, saluted the cheering crowd as he won on his sixth match point.
"It felt great to be back on the court and compete again. It's been a while. Obviously, you don't know how you're going to start off," he said.
"I was putting a lot of hours on the court in the last couple weeks, and I played a lot of practice sets, and I had only one match leading up to this tournament in Kooyong.
"In more or less all of these practice sessions, I could feel that I'm hitting the ball well. So I was hoping this is going to obviously continue and be transferred into the first round of Australian Open.
"The first two sets went extremely well, considering that I haven't played for six months. The third was up and down a little bit, but in general it was a great performance."
It was an impressive return to action with the Serb breaking Young's left-handed serve six times, hitting 33 winners and conceding only 27 unforced errors.
"I did have various emotions, mostly good ones: excitement, joy, gratitude for being able to have an opportunity to compete," Djokovic added.
"About three weeks ago I didn't know whether I'm going to play in Australia or not.
"I was looking forward to getting out on the court and compete. But I did feel nerves and I did feel a bit skeptical whether I'm going to be able to continue playing well as I have in the last couple weeks in the practice sessions.
"But I thought I controlled it well. I didn't get carried away by anything, I just didn't allow it to happen. Very, very solid performance."
Asked if he felt rusty after his months out of the game, Djokovic replied: "There were not too many things I didn't feel so good about.
"There were certain parts of the match, maybe in the third set, where I didn't capitalise on all these opportunities, break points, match points.
"Maybe I should have just approached these kind of points with a little bit more of intensity, a little bit more of aggressivity, but I haven't."
He added: "It's fine. I won a straight-set match. After six months, there's not much to say in a negative note about it."