[2][3] Ahearne entered Straits Settlement Government service as a cadet in 1910[4] and was attached to the Indian Immigrant Department in Penang.
[2] Ahearne was part of the important commission in 1925, on special duty for Indian Immigration Committee in connection with the Avadi Water Supply and Drainage as well as proceed to Assam to investigate labour condition in British India.
[2] Ahearne was the Controller of Labour for Malaya in 1930 and in the following year as the leader of the Straits Settlements Delegation to the International Shipping Conference held in Simila.
[2][3] In 1933, he was on a special duty to lead a Malayan delegation to New Delhi to discuss on the immigration questions with the Indian Government.
[3] Ahearne was invested with Companion of the Most Distinguished Order of St. Michael and St. George (CMG) in 1939.