 After holding the appointments of first class magistrate, district magistrate, senior magistrate and acting puisne judge, Hearne was appointed as a puisne judge (High Court judge), Tanganyika Territory (East Africa) in 1933/1934, where he acted as Chief Justice in 1935 and 1936.In 1936/1937, he was appointed a puisne judge in Ceylon, and sat in the Supreme Court in Colombo.He stayed there for most of the Second World War.