Walter Batchelor MacDougall was born in Mornington, Victoria, on 6 April 1907, the son of a Presbyterian Minister, Reverend Daniel MacDougall, who had emigrated from Scotland, and his Australian-born wife, Rachel (nee Gibson). Walter was educated at Scotch College in Launceston and then Scotch College in Melbourne before taking up farm work in country Victoria. From 1931 to 1939 he served as assistant missionary at Kunmunya Mission in the Kimberley region of Western Australia. JRB Love (see AA 187) was the superintendent of the mission at that time. As well as assisting in church services and other religious duties, MacDougall supervised pastoral and building activities on the mission and managed the store. He married Gladys Giles, a teacher at the mission, in November 1932. In 1938 an accident with a loaded rifle resulted in MacDougall losing the thumb and forefinger on his right hand.

MacDougall and his wife left Kunmunya in 1939. In May the following year he was appointed acting Superintendent of the Ernabella Mission in north-west South Australia. When JRB Love arrived in 1941 to take over as superintendent, MacDougall remained as overseer of pastoral activities on the mission. He enlisted in the Australian armed forces in 1942 and drove trucks carrying supplies from Alice Springs to Darwin until his discharge in 1944. He and Gladys returned to Ernabella, where they remained until late 1946. They then moved back to Victoria.

In the following year, MacDougall was appointed Native Patrol Officer (NPO) by the Commonwealth Department of Supply. His duties were to protect Aboriginal people during the proposed rocket tests at the newly established Woomera Rocket Range in northern South Australia. Based at Woomera, he carried out long-range patrols into central Australia and north-west Western Australia to make contact with Aboriginal people still living in the desert, and others resident at missions and ration depots who might traverse danger areas. He was also required to undertake general welfare duties with Aboriginal people who worked on the pastoral stations in the Woomera area. After 1953 he was given the added responsibility of ensuring the safety of Aboriginal people during the British nuclear tests at Emu and Maralinga. Gladys MacDougall lived at Woomera where she worked as a teacher, and raised their only child, a daughter.

During his employment as NPO, MacDougall corresponded frequently with NB Tindale (see AA 338) at the South Australian Museum, and occasionally donated artefacts, plant specimens, photographs and other items to the Museum collection. In April-May 1957 Tindale accompanied MacDougall on one of his patrols to Giles Meteorological Station in the Rawlinson Range (WA), Mt Davies in north-west South Australia and the Birksgate Range and Blythe Range area, south of Mt Davies (see Tindale journal AA 338/1/22/1). In October-November 1963 Tindale accompanied MacDougall on another patrol to the Rawlinson Range area and also visited Mt Davies (see Tindale Journal AA 338/1/26).

Walter and Gladys MacDougall were founding members of the Woomera United Protestant Church. Walter was also a founding member of the Woomera Natural History Society. He was awarded the British Service Medal on 13 June 1970. MacDougall retired as NPO in 1972 and moved with his wife and daughter back to Victoria. He died on 5 May 1976 and his ashes were later scattered at Ernabella.

Most of MacDougall's patrol reports were collated together during the Royal Commission into British Nuclear Tests in Australia in the mid 1980s and copies of those reports are now available in State Records of South Australia and some interstate institutions. His original field note-books, photographs, cine-films, maps and other data have never been located and it is presumed that they were destroyed after his death. MacDougall frequently corresponded with Tindale about Aboriginal sites and culture (see Anthropology and Archaeology Correspondence files, AA 298) and there is also some correspondence from MacDougall in the JB Cleland collection (see AA 60). MacDougall also donated many stone artefacts and other ethnographic items to the SA Museum at various times between the 1950s and the 1970s.