Mr Walker, who is also facing a police inquiry surrounding an allegation of rape, sat alone at the back of the parliament as he arrived for the final 30 minutes of yesterday’s sitting.
The Dunfermline West MSP was seen sprawled out over his seat as he loudly clapped, cheered and banged his desk when the SNP’s infrastructure cabinet secretary Alex Neil made a speech on the Scotland bill.
Senior MSPs entering the chamber such as former presiding officer Alex Fergusson and former Scottish Lib Dem leader Tavish Scott appeared to deliberately look away from Mr Walker, who had no-one sitting either side of him.
Mr Walker refused to answer questions as he arrived at Holyrood during the evening to vote with the SNP at the end of the Scotland Bill debate. He repeatedly said “no comment” to a series of questions linked to his expulsion amid allegations concerning his three former wives and domestic violence.
Brian Adam, the SNP’s chief whip at Holyrood was seen briefly speaking to Mr Walker, who was previously told he could no longer sit with SNP MSPs.
Mr Walker, who sat behind the Green MSPs Patrick Harvie and Alison Johnstone, also appeared to be ignored by other MSPs as he got up from his seat to get a glass of water at the back of the chamber.
The 71-year-old MSP walked out of the Holyrood chamber alone after the vote, but was forced to return when he remembered that he had left his parliamentary pass at his seat in the chamber.
Meanwhile, the MSP issued a statement before his return to Holyrood yesterday insisting he had never “assaulted” anyone.
Mr Walker went on to claim allegations against him were part of a “orchestrated smear campaign, to which I shall not be succumbing”, as he insisted that he would not resign as an MSP.