On 4 March 2012, the Sunday Herald published claims that his three previous marriages had ended with allegations of violent behaviour towards his wives. The same day, the Scottish National Party suspended him for allegedly not declaring similar claims cited in no-contest divorce actions dating back many years. The SNP expelled Walker on 8 April for allegedly not declaring the allegations cited in his uncontested divorce proceedings during the MSP vetting process. He continued to sit in the Scottish Parliament as an Independent and appealed his expulsion.
A case was brought against Walker and was heard at Edinburgh Sheriff Court on nine days over a two-week period and adjourned on 2 August 2013. On 22 August 2013, Walker was convicted of 23 charges of assault and one breach of the peace in relation to three ex-wives and a stepdaughter.
He attacked three former wives and a step-daughter between 1967 and 1995.
The MSP, who was expelled from the SNP in April after the allegations surfaced and now sits at Holyrood as an independent, denied the charges.
The law states that any elected member jailed for more than one year will be disqualified.
However, in summary cases heard in sheriff courts in Scotland, the maximum sentence that can be handed down is one year, allowing Walker to remain as an MSP.
Politicians from all parties, including Labour leader Johann Lamont, Tory leader Ruth Davidson and her deputy Jackson Carlaw, have signed the motion from Liberal Democrat leader Willie Rennie.
It states: "The parliament believes that Bill Walker MSP should vacate his seat in the parliament immediately."
Mr Rennie told BBC Radio Scotland it was time for Walker to stand down.
"We cannot allow a wife-beater to take his place back in parliament as if nothing has happened," he told the Call Kaye programme.
"And that would be the message it would send to all these women who have been beaten up by their partner?
"What would they think about their parliament acting in that way?"
Mr Rennie said he had already had people from Walker's Dunfermline constituency contact him instead of their MSP "because they believe that Bill Walker cannot represent them any more".
By early September a majority of MSPs had also backed a motion calling on him to resign. On 7 September 2013, he resigned from the Scottish Parliament, claiming there had been a "media onslaught" against him.
On 20 September 2013, he was sentenced to 12 months in prison by Edinburgh Sheriff Court. When sentencing him, Sheriff Kathrine Mackie said "Having regard to the gravity of these offences as a result of the cumulative effect of them, your extreme denial and complete absence of any remorse, and the assessment of risk, I have come to the conclusion that a custodial sentence is the only appropriate disposal. In my opinion, the repeated abuse and violent behaviour towards your three former wives and stepdaughter over a period of 28 years outweighs other factors."
Within a few weeks, lawyers acting on his behalf appeared at the High Court in Edinburgh to appeal against a custodial sentence and this was quickly dismissed.
He was released from HM Prison Dumfries on 21 March 2014 under automatic early release rules after serving half of his sentence. On 17 April 2014 his appeal against his conviction was turned down.