Mendelsohn won for his role as Danny Rayburn on the Netflix series Bloodline, beating out Kit Harrington and Peter Dinklage (Game of Thrones), Michael Kelly (House of Cards), Jon Voight (Ray Donovan) and Jonathan Banks (Better Caul Saul).
Meanwhile, Game of Thrones has become the most awarded narrative series of all time, dominating the list of winners from this year`s awards.
Mendelsohn was also nominated in the same category at last year`s Emmys, but lost to Dinklage, and also received a Golden Globe nomination for the role earlier this year.
He was not present at the Emmys ceremony to collect his award.
Netflix announced last week that Bloodline would end after the upcoming third season.
Mendelsohn began his acting career on Australian TV series including The Henderson Kids, A Country Practice and Neighbours in the 1980s, before a breakout film role in The Year My Voice Broke.
But it was his turn in Animal Kingdom in 2010 that propelled him, and co-stars Joel Edgerton and Jacki Weaver, into the spotlight in Hollywood.
He will appear in Star Wars franchise film Rogue One later this year and is due in Steven Spielberg`s Ready Player One in 2018.
Emmys 2016: Ben Mendelsohn wins best supporting actor award
19 September 2016
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Australian actor Ben Mendelsohn has won a best supporting actor award at the Emmys in Hollywood.
