Desmond Browne QC, for News Group Newspapers, which publishes The Sun, had fought the case for the newspaper to publish "partly naked" photos of Ned RocknRoll.
"We say he is a public figure. Mr RocknRoll has propelled himself into the position of public figure," he told Mr Justice Briggs, adding: "He tries to pretend his lifestyle is not rock and roll at all. That does not hold water."
He said Mr RocknRoll took a job at his uncle Sir Richard Branson's Virgin Galactic and "apparently made up for himself" the job title of "Head of Astronaut Relations and Marketing".
Mr Browne said Mr RocknRoll was not embarrassed at the party and said the photographs were posted on Facebook for "all to see" as part of an "innocent joke".
"If it was so innocent what is the problem? Why not let the public judge what is acceptable behaviour?" he added.
Embarrassing party photos of Kate Winslet's husband Ned RocknRoll obtained by The Sun were "taken by a private individual" and were "not intended to be seen by the world at large," his barrister, David Sherborne, told the High Court.
Mr Sherbourne told Mr Justice Briggs that although the images were on Facebook, they would require "some pretty specialist knowledge" to access them.
"This cannot possibly be described as 'in the public domain'," he said, adding that The Sun had intended to ridicule his client.
"The intention (is) to say something embarrassing about Miss Winslet's future husband," he said.
Kate Winslet and Ned RocknRoll have explained why they sought legal action to prevent "embarrassing" photos of him at a fancy dress party from being published in the press.
The couple issued a statement after a High Court judge blocked The Sun from printing the images from 2010.
We have stopped The Sun from publishing semi-naked photos of Ned taken by a friend at a private 21st birthday party a few years ago. The photos are innocent but embarrassing and there is no reason to splash them across a newspaper.
We recognise that in the internet age privacy is harder and harder to maintain. But we will continue to do what we can, particularly to protect Kate's children from the results of media intrusion. We refuse to accept that her career means our family can't live a relatively normal life.