She also described him as a rude bastard and dysfunctional leader.
Going back to the 2010 political coup led by her friend, former PM Julia Gillard, Ms Roxon said on Wednesday at a small gathering of Labor members at the yearly John Burton lecture at Melbourne's Wheeler Centre that "Removing Kevin was an act of political bastardry, for sure, but this act of political bastardry was made possible only because Kevin had been such a bastard himself."
The once-health minister pointed out that Mr Rudd had an interfering and demanding approach that ministers and public servants struggle to cope with their tasks.
He also often arrived late and demanded schedule changes that the Labor government had to pay for 20 unused hotel rooms because Mr Rudd failed to appear on a calendared hospital visit and went instead to another Australian city, Ms Roxon recalled.
But while it was right to kick Mr Rudd out of office in 2010, Ms Roxon admitted the ouster was handled clumsily that had the former PM complained, he would have won an unfair dismissal lawsuit.
She blamed his refusal to recover with dignity from his power loss to failure of Labor to find a united voice. To address this lack of unified voice, she proposed for ALP to give its rank-and-file members more say in party affairs or face frequent challenges from independents and smaller parties.
The former AG hinted that Mr Rudd has a messianic complex, describing him as having a fatal attraction to everyone else's problem. She concluded by saying that Mr Rudd should not only quit Parliament but leave politics altogether.
Ms Roxon's beef with Mr Rudd goes a long way back as this interview with SkyNews Australia a year ago confirms.
In response to Ms Roxon's statements Labor frontbencher Chris Bowen called on party member to show some respect for past leaders.
"All former Labor leaders are deserving of respect ... The Australian people are over the discussion about what happened over the past six years and interested in a discussion about the future," ABC radio quoted Mr Bowen, a key backer of Mr Rudd.