It has long been my understanding that he is. He's also Australian.
It’s been my long understanding that he is not.
From wikipedia:
Keith Rupert Murdoch was born on 11 March 1931 in Melbourne, the second of four children of Sir Keith Murdoch (1885–1952) and Dame Elisabeth (née Greene; 1909–2012).[21][22]: 9 He is of English, Irish, and Scottish ancestry. His parents were also born in Melbourne. His father was a war correspondent and later a regional newspaper magnate owning two newspapers in Adelaide and a radio station in a faraway mining town, and chairman of the Herald and Weekly Times publishing company.[7][23]: 16 [24] Murdoch had three sisters: Helen (1929–2004), Anne (born 1935) and Janet (born 1939).[25]: 47 His Scottish-born paternal grandfather, Patrick John Murdoch, was a Presbyterian minister.[26] Later in life, Murdoch chose to go by his second name, the first name of his maternal grandfather.
https://en.wikipedia.org/wiki/Rupert_Murdoch