Mr Hastie was called to give evidence in defamation proceedings launched by the Victoria Cross recipient over allegations he committed war crimes in Afghanistan, bullied colleagues, and assaulted his mistress.
Mr Roberts-Smith, 43, denies all the claims reported by The Age, The Sydney Morning Herald and The Canberra Times, who are defending them as true.
Over two days of evidence last week, Mr Hastie - a captain in the Special Air Service Regiment between 2010 and 2015 and now the assistant minister for defence - told the Federal Court hearing that he had heard allegations about Mr Roberts-Smith from many people.
One man told him Mr Roberts-Smith punched him while they were deployed, while others recounted bullying and an incident where he allegedly shot a corpse.
Mr Hastie also came to believe Mr Roberts-Smith had been involved in an execution of an Afghan.
Mr Roberts-Smith's lawyers have repeatedly suggested allegations against the war hero were made up by a small group of peers who were jealous of his military accolades.
But Mr Hastie listed 20 people who had suggested to him that Mr Roberts-Smith was a hypocrite – that "the outward facing picture of Mr Robert-Smith was at odds with his battlefield conduct".
It was a far cry from the initial impression he had of Mr Roberts-Smith, who had given Mr Hastie a tour of SAS facilities in 2009 before he joined the regiment.
"I started from a very high regard for Mr Roberts-Smith… (but) I'm no longer proud of (him)," he said on Friday.
However, Mr Hastie denied disliking him, saying his family prayed for him.
"I pity him."
"I don't want to be here... this is terrible for our country. It's terrible for the SAS. It's terrible for the army."
Mr Hastie denied he'd been critical of Mr Roberts-Smith to raise his own profile as a parliamentarian, and that he'd come to court to support the newspaper's claims because they were giving him financial assistance in another legal matter.
