Robert Augustus Kerrigan was born in East Melbourne, Victoria, in May, 1874. His father, John Kerrigan (1834-1907) was then 40 years old, his mother, Mary, nee Kilgar/Kilgour (1842-1878) was then thirty two years old. Robert was one of nine children: William b.1861, Helena b.1866, Matthew b.1868, Mary-Anne b.1870, Patrick b.1972, Robert b.1874; Catherine b. 1875, and Christopher b.1877. There was also Edward, but his birth date is unknown. Their mother, Mary Kerrigan died in 1878, when Robert was only four, and John Kerrigan died in 1907 at 'Tara' Launching Place, Victoria. 

Robert Kerrigan enlisted for World War 1 on 29 December, 1916, when he was 42 years and 7 months old. He was married, and gave his wife Jane, as his next of kin, living at 1205 Hoddle St., East Melbourne. He was an Engineer with the Victorian Railways, 5' 8" tall and probably one of the few volunteers with grey hair. By religion, he was Roman Catholic.

With his skills, he must welcomed into the armed forces, in spite of his age. He was placed with the Railway Unit, Section 2, promoted to Fitter on 8 January, 1917, with 8/- pay per day, 2 shillings more than an ordinary soldier. He was quickly despatched to the war, embarking from Melbourne on 19 February, 1917, on board H.M.A.T. Ballarat A70 and arriving in England on 27 April. He marched in to Borden on 27 April, and was then sent over to France on 29 May. On 31 May, he was ill, and placed in isolation, though the illness is not recorded in his record. On 23 May, he was released from convalescent camp, marching in to the Australian General Brigade Division at Havre. He was discharged to duty on 26 August, after marching in from a Reinforcements Camp.

On 24 August, 1917,  Robert Kerrigan was again in hospital, this time with scabies, where he probably spent about three days. On 13 September, he was ill again, and taken to the 55th General Hospital at Boulogne, suffering from Trench Fever. On 25 September, he was transferred to the 14th Convalescent Depot with 'neuritic dysentery'. On 12 October, he was discharged to Base Depot. He did not return to duty until 4 November, and was assigned to a permanent base,  the 15th Railway Operation Company, presumably in England. 

On 5 December, 1917, Robert Kerrigan marched in to the No. 2 Command Depot in Weymouth from France. On 21 December, he left the depot, prepatory to being returned to Australia. He had been declared medically unfit, suffering from shell shock, trench fever, and was identified as over age.He returned on the Persic A34,  and disembarked in Melbourne on 12 February, 1918. 

After the war, he was granted a pension of 30/- per fortnight, active from 16 March, 1918; his wife, Jane Kerrigan, also recieved a pension, 15?- per fortnight. It's hard to follow them from there. In 1928 and 1`929, they were at 252 Barkly St. North Fitzroy.The Electoral Rolls from 1922-1935 have them living at 8 Fulton St., Armadale. His death certificate says that Robert Kerrigan died in 1939 and it is possible he was still living in Armadale,, but there is no indication of where he died or is buried.