Finland's 2007 world champion made the most of having to make just two pit stops and was pulling away from his rivals, having just set the fastest lap time of the race, when he crossed the line 12.4 seconds clear of Ferrari's Fernando Alonso.
"It was probably one of my easiest wins," said the 'Iceman', cool as ever after a 20th career win that equalled the tally of retired double champion and compatriot Mika Hakkinen.
Sebastian Vettel, seeking to win his fourth successive world title this year, rounded out the podium in third place for Red Bull after struggling with tyre wear throughout the race.
Alonso's Brazilian team mate Felipe Massa finished fourth ahead of 2008 champion Lewis Hamilton who had an encouraging first race for Mercedes after leaving McLaren.
Vettel had got away cleanly from pole position but the variety of strategies forced on the teams by the tyres and the pace shown by Red Bull's rivals ensured this was never going to be a procession.
A few light showers contributed to an intriguing race but never threatened to disfigure it as top drivers engaged in fierce battles around the circuit and the lead changed hands with surprising frequency.
Seven cars led the race at one stage or other but after Raikkonen hit the front for the second time on lap 43, it looked like only mechanical failure would stop him.
"I had a very good car all weekend," said Raikkonen, the former McLaren and Ferrari driver who made his comeback last season after two years in rallying, on a podium of champions.
"You just have to get through the early laps in the first race of the season. Near the end, I was still pushing because I knew Fernando was catching up a bit and I thought at some point we would need a little extra if the rain came again.
"We are happy with the win but there's an awful lot of work to do to win the championship."
It was the first season-opening win by a team called Lotus since American Mario Andretti won the 1978 Argentine Grand Prix.
Red Bull's Mark Webber made a terrible start from the front row, suffering telemetry problems on the grid and losing KERS for the first part of the race, and finished sixth in his 12th attempt to win his home grand prix.
The Australian said the team, constructors' champions for the last three years, were not in as good a position as they had thought.
Vettel was more sanguine about his results even if he had hoped for more after dominating qualifying, which had been completed on Sunday morning after torrential rain on Saturday.
"Of course we wanted more, when you start from pole you expect to win," he said.
"But we could see from the first few laps that the tyres were falling apart. Sometimes we have to admit that other people are faster than us.
"I think the naked pace was there ... (but) we couldn't keep it up and the times set at the front by Fernando and especially Kimi were very impressive and obviously we couldn't do that."
Adrian Sutil, returning to the sport after a year out, enjoyed a long period as the unlikely leader of the race before finishing seventh, just ahead of his Force India team mate Paul Di Resta. Both also benefited from a two stop strategy.
Alonso grumbled afterwards about being held up by backmarkers as he attempted to chase Raikkonen down but was unable to disguise his delight at his car's pace.
"We are very happy, we had a difficult start two years ago and again last year but this year it's different," said the twice champion, who missed out on the final qualifying session in Australia last year.
"We feel much more comfortable, the car is responding well and is competitive. We have a good season ahead of us. We only have five days to prepare for the next race but we will again be a tough opponent."
McLaren's problems continued and Jenson Button, the winner of three of the last four races at Albert Park, was only able to manage ninth place while his new team mate Sergio Perez was 11th.
"We are not quick enough and there's a lot of work we need to do to move forward and challenge the front guys," said Button. "We are a long way off."
Raikkonen's French team mate Romain Grosjean claimed the final point for Lotus in 10th.
In a race that featured more overtaking than retirements, Pastor Maldonado beached his Williams on the trackside gravel on lap 25 and Nico Rosberg followed him out of the race when his Mercedes developed an electronics problem a lap later.
Nico Hulkenberg will have to wait until next week's Malaysian Grand Prix to get his season underway after a fuel system failure on his Sauber prevented him from starting.
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