Mr Walter Donald Douglas was born in Waterloo, Black Hawk County, Iowa on 21 April 1861.

He was the son of George B. Douglas (1817-1884), an oat meal manufacturer, and Margaret Boyd (1825-1901). His father was Scottish, hailing from Thurso, whilst his mother was Irish, a native of Co Tyrone; they were married in Lee County, Illinois in 1855. His father was a partner in a cereal mill in Cedar Rapids which later merged with several other oat mills in 1901 to form Quaker Oats Company. Walter had two brothers: George Bruce (1857-1923) and William Wallace (b. 1864).

The family appear on the 1870 and 1880 census records residing in Cedar Rapids, the 1880 schedule confirming their address as Iowa Avenue. Following high school Walter attended the Shattuck Military Academy in Faribult, Minnesota and later, with his elder brother George he formed the Douglas and Company Starchworks (later Penick & Ford) in 1903.

He was married on 19 May 1884 to Lulu Eliza Camp (b. 31 October 1862), also a resident of Cedar Rapids, and they had two sons: George Camp (1885-1925) and Edward Bruce (1887-1946). Lulu died on 12 December 1899 aged 37.

A widowed Walter and his two sons were shown on the 1900 census living back with his mother who passed away the following year. Walter was remarried in New York on 6 November 1906 to Mahala Benedict, née Dutton (b. 1864), a divorcee originally from Cedar Rapids.

Described as a ''Captain of Industry,'' Douglas had amassed a fortune of at least $4 million in various Cedar Rapids industries and branched out into the linseed oil business in Minneapolis. He was associated with several prominent businesses, including the Saskatchewan Valley Land Company, Canadian Elevator Company and the Monarch Lumber Company; and was an executive in the Quaker Oat Company which his father co-founded.

Douglas' 1911 passport describes him as standing at 5' 8", with a full face, grey hair, fair complexion, grey eyes, and a large nose. 

With his second wife Mahala he built a mansion on bluffs overlooking Lake Minnetonka near Minneapolis that was said to be a copy of a French palace. Douglas retired on 1 January 1912 and the couple took off on a three-month tour of Europe to find furnishings for their palatial retreat, known as Walden.

For their return to the USA, the Douglas couple boarded the Titanic at Cherbourg (ticket number 17761 which cost £106, 8s, 6d), together with their French maid Bertha Leroy and they occupied cabin C86. Whilst aboard they became acquainted with other Minnesotan passengers; Mr and Mrs John Pillsbury Snyder, Mr and Mrs William Baird Silvey, and Miss Constance Willard.

On the night of the sinking Mr and Mrs Douglas had been in their cabin at the time of the collision, the shock of which was so slight that they paid little heed to it. Receiving no instructions to go topside, the couple waited in their cabin, he reassuring his wife that there was no danger. Only the sight of other passengers gathering in the corridors dressed in lifebelts prompted to couple to do the same and they dressed and headed to the boat deck where they waited for some time. Mr Douglas saw his wife and maid off in lifeboat 2 but refused to go himself until all women and children were accounted for, saying it would make him 'less than a man' or 'No, I must be a gentleman.' According to later reports Walter Douglas, dressed in his finest, helped lower the last lifeboat of survivors off the Titanic.

Mr Douglas died in the sinking and his body was later recovered by the cable ship MacKay Bennett (#62):

Upon hearing the news of the disaster his brother George and his wife Irene hastened to New York and arrived on 18 April, the same day the Carpathia would dock. Douglas' body was brought back to his hometown of Cedar Rapids where he is buried alongside his wife in the Douglas family mausoleum at Oak Hill Cemetery.

His widow Mahala never remarried and remained living in Minnesota before her eventual demise in California in 1945.