Labor upper house member Craig Farrell was elected Legislative Council president on Tuesday.
Mr Farrell had not publicly declared any interest in taking the chair until Tuesday.
Independent MLCs Mike Gaffney, Kerry Finch and Ms Rattray had previously each shown interest in the position but Mr Farrell was elected via a secret ballot before Question Time.
He has previously held the role as Leader of Opposition Business in the Legislative Council as well as Labor's transport portfolio.
A Labor spokesman said these roles would be reassigned in due course.
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The promotion wins his an additional $49,065 on top of his base salary of $140,185.
As president, Mr Farrell would only be to use his casting vote if the numbers were tied on a motion or piece of legislation.
He said in a statement he was honoured to be elected president and would treat the position with respect and dignity.
"From the outset, I want to make it clear that I will remain a member of the Labor Caucus," Mr Farrell said.
"I will also reserve my right to vote on matters according to my Labor values at times when a casting vote is required and respect the critical role of the Legislative Council."