The Costello family took up mining grazing leases at Thanes Creek in 1881.

[1] He was awarded the Distinguished Service Order for bravery during the Battle of Semakh, on the Sea of Galilee on the 25 September 1918.

[1] In 1920, Costello, as a Country Party candidate, won the seat of Carnarvon in the Queensland Legislative Assembly.

[1] In 1924, Costello married Ruth Evelyn Harn (died 1969)[2] and together had two sons and two daughters.

[1] He was a stalwart of the RSL Warwick Subbranch and a former patron of the Spurs and Feathers Club.