During World War II, she volunteered to serve with the Women's Auxiliary Territorial Service (ATS) and was posted to Edinburgh Castle as a clerk with the Scottish Command.
She was referenced in the book, Debs at War 1939-1945: How Wartime Changed Their Lives, written by Anne de Courcy.
After her husband returned to civilian life following World War II, she played an active role in helping him run his family estates in Dunbartonshire and Lanarkshire.
Lady Whitelaw served on the Lakeland Horticultural Society and was vice-president of the Penrith and District Gardeners' and Allotment Holders' Association.
[2] Lady Whitelaw was heavily involved in charity work and philanthropy, including Barnardo's, British Red Cross, the Blencowe Women's Institute, Wives of Westminster, the Eden Valley hospice (in Carlisle), and the Yellow Brick Road Appeal of the Children's Foundation.