[4][5] His father was David Lahey, an Irish-born farmer and timber miller, and his mother was Jane Jemima (née Walmsley), a homemaker.

Recognising the value in preserving the forests, he tirelessly campaigned, which resulted in the establishment of Lamington National Park in July 1915.

[4][10][11][12] In April 1930, Lahey founded the National Parks Association of Queensland (NPAQ), where he served as president till his death in 1968.

[6] Lahey, NPAQ secretary[13] Arthur Groom and a few supporters of theirs are credited for founding Queensland Holiday Resorts Limited and establishing Binna Burra Mountain Lodge, located next to Lamington National Park.

[4] In World War I, he enlisted in the army, serving with the 3rd Divisional Engineers, initially attaining the rank of second lieutenant.