The Western Australian Labor Senator-elect currently serves as the National Vice President of the Shop, Distributive and Allied Employees Association.
SBS contacted the WA Labor office numerous times via phone and email, but no response was received by Mr Bullock by time of publishing.
The union heavyweight – who previously served with the National Union of Workers among others – made headlines when he was elevated to the top of Labor’s WA Senate ticket above departing Senator Louise Pratt.
He came under the spotlight again when comments he made during a November address were made public, prompting backlash over his description of Labor as untrustworthy and full of “mad” members.
Senator Pratt has also made a number of public comments about her replacement, describing him in April as “someone who I have known for many years to be deeply homophobic, to be anti-choice, and has recently emerged disloyal to the very party he has been elected to represent”.
Addressing the Senate in her farewell speech last week, she highlighted the “public failures of Labor” in the western state.
Speaking to ABC Radio ahead of the Senate revote, Mr Bullock said the party had assessed him as “being the best man for the job”.
“What I’m entering the Parliament with the hope of doing is to stop the excesses of the Abbott Government in stripping away the rights of workers and to expose their callous disregard for the growing numbers of unemployed people in this country,” he said.
“… They don’t rate the interests of workers at all. I do.”
Anthony Albanese has also offered support for Mr Bullock, saying there was no doubt controversies hurt the party’s vote, but he should serve his term.
Opposition Leader Bill Shorten also backed the Senator-elect.