Federer completed a career Grand Slam and a record equalling 14th major, with a 6-1, 7-6 (7/1), 6-4 win over Söderling.
The 27-year-old world number two finally won a Roland Garros crown at the 11th attempt and in his fourth successive final having come up heartbreakingly short in the last three showdowns against Spanish nemesis Rafael Nadal.
His victory, ironically over the Swedish 23rd seed who shocked four-time Nadal in the last 16, took him level with great friend Pete Sampras as the holder of 14 Grand Slam titles.
He also moved into a select group made up only of Fred Perry, Don Budge, Rod Laver, Roy Emerson and Andre Agassi as men who have won all four of the Grand Slam events.
“It was probably my greatest victory, I was under big pressure. I did it and it’s phenomenal,” said Federer who broke down in tears after being presented with the trophy by Agassi, the 1999 champion, and while the Swiss national anthem was played.
“It was great to be on the podium as a winner for a change. Andre said it was my destiny to win this and that I deserved it.
Federer, who sent down 16 aces in the final, added: “Until the end of my career, I can play peacefully knowing that I will never again hear it said that I never won Roland Garros.”
Söderling, who has now lost 10 times in 10 meetings with Federer, admitted the Swiss was a deserving winner.
“Roger was too good for me today, he played much better. He is a worthy winner and for me he is the best player in history,” said Söderling.
“He gave me a lesson in how to play tennis.”
Any doubts over Federer’s ability to overcome his Paris jinx were quickly dashed as the Swiss star, playing in a record-equalling 19th Grand Slam final and riding a tidal wave of support, dominated Söderling.
He broke the first game on a Söderling double fault and was soon a second break to the good to lead 4-0 when a sweetly-timed drop shot left the Swede stranded behind the baseline.
Söderling, the first Swede in the Roland Garros final since his coach Magnus Norman finished runner-up to Gustavo Kuerten in 2000, stopped the rot with a hold to trail 4-1, but Federer quickly nipped further ahead to 5-1.
Söderling’s uncompromising forehand, which was a dagger to the heart of Nadal, was looking more like a blunt instrument in the damp and chilly conditions.
His service game crumbled again in the seventh game as Federer claimed the opening set.
It had taken just 23 minutes with the Swiss losing just two points on serve.
The final was then delayed by a worrying security breach during the fourth game of the second set with Federer ahead 2-1.
A spectator, dressed in red, waved a flag of the Barcelona football club in the world number two’s face before he was wrestled off Court Philippe Chatrier by security guards.
But the Swiss star wasn’t disrupted from his elegant stride, either by the intruder or the rain which started to steadily fall.
Although Söderling slowly rediscovered his service power, it was Federer who was comfortably dictating the points and he fired down four aces in the tie-break to open up a two-sets lead.
He was a break ahead in the third set to lead 1-0 before Söderling carved out, and squandered, his first break point of the match in the fourth game.
Federer then sent down his 16th ace of the tie to stretch to 4-2.
He came out to serve for a place in history but faltered to 30-40 with a wild, running forehand.
With pregnant wife Mirka looking anxiously on, he averted the crisis and went to match point with a confident volley and claimed victory when Söderling netted a service return after 1hr 55min on court.
A tearful Federer slumped to the Paris clay in celebration as he secured his place as arguably the greatest player of all time.