Down 16-6 at the break and still trailing by 10 points with 20 minutes left, Wales ran in two tries to record its first win at Twickenham in 20 years.
"It's the most fantastic day of my career," Jones said.
"It was a fantastic effort and the win was thoroughly deserved. Even when we were 10 points down we had belief in ourselves.
"We came here with a small squad and we turned them over on their own patch," the No. 8 added.
Fly-half James Hook was named man of the match after nailing six out of six goal kicks and playing a crucial role in his side's first try.
Wales' last visit to Twickenham, before the World Cup, ended in a record 62-5 defeat and Wales' new coach, a proud Warren Gatland, said the significance of Saturday's scoreline could not be underestimated.
"The result is everything. It's a monkey off the guys' back. They showed a lot of guts and dug deep," he said.
But former Ireland boss Gatland admitted that, at half-time, hopes of Wales' first win at Twickenham since an 11-3 success in 1988, were in the balance.
"The first half was very poor," the New Zealander said. "The message before half-time was to hang in there and not concede again, play a bit of rugby and respect the ball. The pleasing thing was the longer the game wore on the stronger we got."
Shaun Edwards, who has a part-time Wales role, said the visitors' defence in denying England a second try, when hooker Huw Bennett got his arm under the ball as Paul Sackey plunged over, had been crucial.
"The defensive set in the last five minutes of the first-half was vital," said Edwards, whose team were rocked by Toby Flood's 23rd minute score.
"They only scored one try and that was from a kick. To concede only one try from a kick at Twickenham is very creditable."
Gatland, looking ahead to Wales' next match at home to Scotland a week on Saturday, warned fans against expecting too much too soon.
England coach Brian Ashton, whose team now faces a tricky task away to an Italy side that ran Ireland close before losing 16-11 on Saturday, was at a loss to explain his team's collapse.
■Under fire Ireland coach Eddie O'Sullivan admitted he was happy to accept winning ugly after his World Cup flop stumbled to a 16-11 Six Nations victory over Italy at Croke Park.
The Irish failed to build on a 10-3 lead in the first-half which brought back memories of their dreadful World Cup where they went out in the first round.
However, O'Sullivan insisted that the first match of every Six Nations was a tough battle. "In the context of the Six Nations I am happy enough to take this," O'Sullivan said. "Of course we wanted to hit the road running but, just as we did two years ago against Italy, and against Wales last year, we struggled. We won ugly and we dug this one out."
Gorsein Boy's take. Overall a great fight back from a team in the building. This will be a fantastic boost for Wales and a disaster for England and thir tried-looking coach. Early days for Wales but they are on the come-back trail.