Hubback began his Malayan career in July 1895 as chief draughtsman of the Selangor public works department, when it was fully extended in the construction of new government offices (later the Bangunan Sultan Abdul Samad), which the forceful state engineer, Charles Edwin Spooner, had decided should be designed in an eclectic style, new to Malaya, variously known as neo-saracenic or British raj. It had originated in India by a process of ‘architectural miscegenation’ (Davies, 188) that combined Indian Muslim, Hindu, Gothic, and other traditions, as an expression of imperial achievement. Apart from its novelty this style posed structural problems which led Kuala Lumpur ‘old hands’ to predict the collapse of the central tower. But a century later it stood to prove the sceptics wrong. On its completion Hubback left the government service for private practice, but he returned in 1901, and until 1914 he designed a number of large public buildings in the same style though with ingenious variations, including a state mosque (1909), and main railway stations in Kuala Lumpur (1911) and in Hong Kong (Kowloon, 1913). He became an associate of the Royal Institute of British Architects in 1905 and a fellow in 1909. In 1901 he married Margaret Rose Frances (Daisy) Voules, daughter of Sir Gordon Blennerhassett Voules, a judge in India, and sister of a Malayan colleague, Arthur Blennerhassett Voules; they had a son and a daughter. Hubback captained the Selangor cricket team, though he could not equal his brother Theodore [see below], who, keeping wicket for Lancashire, caught W. G. Grace and then hit forty runs off the doctor's bowling. Both were outstanding games players.
Arthur Hubback was also prominent in what became the Federated Malay States Volunteer Force, used both for local defence and in support of the police in maintaining law and order. Under a commandant who lacked any idea of suitable training the new force, formed in 1902, had declined in numbers and morale. When Hubback took charge in 1907 he moved from ‘uninteresting’ barrack square drill to training at weekend camps in musketry and tactical movement (Wright and Cartwright, 598). The force then grew rapidly in strength and efficiency, and a contingent under Hubback attended the coronation of George V in 1911.