The Sun on Sunday sold three million copies after it hit news stands across the country for the first time, Rupert Murdoch said.
The media Tycoon took to Twitter to announce that sales of his new Sunday title exceeded expectations.
He said: "Reports early, but new Sun edition sold 3m!"
On Friday he said that we would be "very happy" if the paper sold more than two million copies.
The newspaper came out today with a pledge of "trust" and "decency" following the damaging phone hacking scandal.
It promised readers it would remain "fearless, outspoken, mischievous and fun".
The newspaper claimed it would hold all journalists to account and said it had appointed a readers' champion to deal with errors and feedback from the public.
In an editorial, the newspaper also commented on the arrests of 10 current and former employees over alleged corrupt payments to public officials, saying they were "innocent until proven guilty".
It said that the closure of its sister paper the News of the World, which ceased publication last July at the height of the hacking scandal, was a "sobering experience".
The editorial, titled: A new Sun rises today, said: "As we launch the seven day Sun, we want to strengthen that connection (with the readers) with a new independent Sun Readers' Champion to accept feedback and correct significant errors.
"Our journalists must abide by the Press Complaints Commission's editors code, the industry standard for ethical behaviour, and the News Corporation standards of business conduct.
"We will hold our journalists to the standards we expect of them. After all a newspaper which holds the powerful to account must do the same with itself.
"You will be able to trust our journalists to abide by the values of decency as they gather news."
It said the Sun has been a "tremendous force for good", adding: "It is worth reminding our readers, and detractors, of that as we publish our historic first Sunday edition during what is a challenging period.
"News International closed our sister paper the News of the World over the phone hacking scandal.
"Since then some of our own journalists have been arrested, though not charged, over allegations of payments to public officials for stories. We believe those individuals are innocent until proven guilty.
"It has been a sobering experience for our entire industry."
Mr Murdoch, 80, travelled to the paper's printers in Broxbourne, Hertfordshire, last night to witness the new Sunday tabloid roll off the press for the first time.
The front page of the new title featured an exclusive interview with Britain's Got Talent judge Amanda Holden, the first after the birth of her daughter, which left her in a critical condition in hospital.
The newspaper, which contains 92 pages and a 28-page football pull-out, also features a topless photo of singer Kelly Rowland on page three, but the X Factor judge is covering her modesty.
Bosses at News International have recruited a clutch of celebrity columnists including Katie Price and Nancy Dell'Olio for its latest title, while the Archbishop of York and chef Heston Blumenthal will also have weekly slots.
News International announced the birth of a Sunday edition of the biggest selling UK daily newspaper on Monday and it quickly sold out of advertising space.
The new paper tipped the balance in the lucrative Sunday market after announcing it would be sold for just 50p, prompting a number of rivals to slash their prices.
The Daily Star Sunday had "your best value paper - 50p" emblazoned across it, and the Sunday Express read: "30p cheaper than the Mail on Sunday" written in a prominent font on the front page. However, the People and Sunday Mirror kept their £1 price tag.