The Australians did a celebratory chest bump and hugged tightly after defeating duo Hugo Nys (31) of Monaco and Poland's Jan Zielinski (26) 6-4, 7-6 (7/4), to the delight of the home crowd at Rod Laver Arena.
It was Hijikata and Kubler's first event as a doubles pairing and ensures that the trophy stays in home hands, having been won last year by Australians Nick Kyrgios (27) and Thanasi Kokkinakis (26).
"Rinky and I definitely didn't think this was happening two weeks ago. Bit of a pleasant surprise," said Kubler on court.
"I've got to thank Rinky, he was the reason we teamed up for this tournament. Two weeks later we've got this trophy."