[3] During World War II he served on the Central Wool Committee (1939 to 1942) and chairman of the Country Party from 1940 to 1942.
[3] He did much to improve cattle breeding in Australia: In 1937 he visited America where purchased a selection of stud cattle to improve his Antrim Poll Shorthorn herd.
He was president of the United Stud Beef Cattle Breeders' Association of Australia from 1942 to 1945.
[3] Killen married Irene Ella Henderson on 26 April 1913;[4] they had one son and five daughters.
[6] The Australian politician Jim Killen (1925–2007) was not closely related.