In a widely circulated statement, PR man Iain Maciver suggested Diana Walker was "enjoying the limelight" surrounding Mr Walker's conviction for domestic assault and questioned why she did not leave him sooner.
Political leaders were quick to condemn the remarks which Mr Maciver said later had not been approved by Walker.
In an emailed statement, he said: "Mr Bill Walker did not write that statement. He left it to me to clarify matters about their divorce and the result is all my fault.
"I apologise to Diana Walker who absolutely did not deserve those silly comments and criticism."
Walker, 71, of Alloa in Clackmannanshire, was convicted of 23 domestic abuse charges at the end of a trial at Edinburgh Sheriff Court last month. He carried out the attacks against his three ex-wives and a stepdaughter between 1967 and 1995.
The former SNP MSP, who was ejected from the party when the allegations surfaced, denied the charges. He is due to be sentenced later this month.
He offered his resignation from Holyrood on Saturday, shortly after confirming that Mr Maciver was authorised to act as his media spokesman.
A later statement from Mr Maciver headed ''what Diana Walker always forgets to mention'' said: "Although they had separated, she did not want to divorce him and, in fact, Mr Walker had to divorce her on grounds which she did not deny. If she had been subject to as much abuse as she now claims, why did she not divorce him in the 1990s?
"These are matters of fact, which were said in open court, yet do not seem to feature in the script the former actress is currently working from."
The statement concluded: "Although I have asked Bill Walker to comment on this, he insists he will not."
Scottish Liberal Democrat leader Willie Rennie said earlier today: "Regardless of whether these comments came from his official spokesman or from Bill Walker himself, they are utterly shameful and should be withdrawn."
Scottish Conservative leader Ruth Davidson said: "These comments from Bill Walker's PR man are a disgusting coda to a shameful set of actions.
"Since prosecution he has sought to deny his actions, blame the media and now, bizarrely, claim one of his victims is a self-publicist.
"No victim of abuse should be in any doubt: it is never the 'wrong time' to leave your abuser, as this statement seems to claim. You will not be judged and there is support out there.
"I hope the court takes Bill Walker's foul and self-serving rants into account at sentencing and he gets the maximum possible time in jail. It's regrettable that is wasn't a jury trial so the sentence could be even longer."
Scottish Labour MSP Claire Baker said: "This latest attack on one of his victims is shocking and disgusting. This statement raises even more questions about Bill Walker, but also why this sort of individual was ever deemed fit for public office by the SNP."
Convicting Mr Walker, Sheriff Kathrine Mackie said: "I would observe that why a woman stays in or returns to an abusive relationship is a complex issue not easily understood by the rational observer.
"It does not in my opinion mean that that woman's evidence of the relationship necessarily lacks credibility."
She also said: "I found all the Crown witnesses, and in particular the three principal complainers, credible and reliable."