The daughter of Greek migrants, Cotsis grew up in the St George district together with her brother. She was educated at Canterbury South Public School and at Kingsgrove High School before matriculating to Macquarie University, where Cotsis became a member of the University's Hellenic Studies Foundation and established a program that preserved the Greek language and Hellenic heritage at the University.[4] Graduating with a Bachelor of Arts from Macquarie University, Cotsis later completed a Master of Legal Studies at the University of Technology, Sydney.[5]
In September 2010 Cotsis was appointed to the Legislative Council to fill a casual vacancy following the resignation of John Della Bosca.[5] In September 2016, Cotsis resigned from the Legislative Council after she was preselected to contest the Legislative Assembly seat of Canterbury for Labor at the by-election to fill the vacancy left by Linda Burney, who had resigned to contest the federal seat of Barton at the 2016 federal election.
Following Labor's victory at the 2023 NSW election, Cotsis was sworn in as the Minister for Industrial Relations and the Minister for Work Health and Safety on 5 April 2023.[7]
