Alan Frederick Leigh was the son of William James Thomas Leigh, a baker by trade, and his wife, Elizabeth, nee Mclean. In 1916, when Alan enlisted at the age of eighteen, the family were living at 476 Albert St., East Melbourne, where Elizabeth ran a boarding house. In the 1919 census, Alan was listed as a student, but at the time of his enlistment named himself as a clerk, a profession he was to follow all his life. The family were not new to East Melbourne: In 1909, they had been living at 208 Clarendon St., with Alan's father still working and his mother engaged in home duties. In 1913, they had moved to Fitzroy, but were still close to East Melbourne at 139 Victoria Parade and during the war, they moved again, this time ot 58 Clarendon St. East Melbourne. 

Alan Frederick Leigh (Allan on his enlistment form) was two weeks short of his twentieth birthday, 20 March, when he enlisted on 6 March, 1916. He was already experienced, having served for four years in the Senior Cadets, and was attached to the newly-formed 38th Battalion, B Company, established the same month at Epsom Racecourse. Within a few weeks, then men were transferred to camp at Cambellfield, follwoing a severe outbreak of meningitis at Epsom. On 22 November, 1916, the men embarked on HMAT Runic A54, for England, landing at Southampton. From Southampton, they went for further training, crossing for France in late November, 1916, and were in the trenches of the Western Front on 1 December. The 1916-17 winter was a bitter one, with little real fighting, although the men took part in raiding parties on the German Lines.

The Battle of Messines was their first major battle. The German Army held the Wytschaete-Messines Ridge and it was  essential that the Allies capture it in order to open the way to Ypres. Twelve Australian and New Zealand divisions took part, along with other Allied troops, with the Australian 3rd Division commanded by Sir John Monash. The operation was called 'Magnum Opus' and was supported by 1,500 field guns and 700 heavy guns. It began just after midnight on 7 January, with a bombardment, followed at 3.10 am by the detonation of 19 underground mines, placed in tunnels under the German trenches. The mines exploded in a great roar and with a spectacular column of fire, killing some 10,000 enemy troops, and blowing the top off the Wytschaete-Messines Ridge. The operation finished on 9 June, with the allies commanding what was left of the ridge. The allies lost 17,000 troops in the two day battle, the Germans, 25,000.

Alan Leigh was severely wounded on 7 June, with a severe gunshot wound to his buttock and lower back. He was taken to the 1st General Hospital, Blouogne, then shipped back to England  on the HT St Patrick and admitted to the 1st Southern General Hospital. On 23 August, 1917, he was shifted to the 3rd Auxiliary Hospital at Dartford, then presumably went for convalescence. His fighting days were over. On 13 March, 1918, he returned to Australia for discharge, first on the Dunveigan Castle,  then the HT Tofua. He was discharged from the AIF on 24 July, 1918, at Melbourne.

In 1919, Allan Legh is recorded as living with his parents,  in thier boarding house at 476 Albert St., East Melbourne. He married in 1921, to Lilian Elizabeth Algie, of Armadale, Victoria and they were to have one child, a daughter.He had returned to hsi profession of clerk and they began married life at 124 Alma Rd., St Kilda. In 1924, they were living at 205 Kambrook Rd., Caulfield East where they stayed until 1928. In 1928, they were in Geelong, living at 5 Keera St., Corio and from 1936-1949, they were in East Malvern, at 80 Paxton St.

In the 1960s, Alan and Lilian in Mitcham, then Blackburn, finally moving to 4 Pippin Grove, Glen Waverley in 1977, now a retired couple. They were to stay there until Alan's death in 1980, aged 83.