He was first elected to the House of Commons of Canada in 1917 representing the riding of Waterloo North, Ontario.

He served until 1940, when he was appointed to the Senate representing the senatorial division of Waterloo, Ontario.

[1] He is buried in the Mount Hope Cemetery in Kitchener, Ontario.

[2] As Senator, he waged the campaign to eliminate the ban on margarine in Canada.

[4] There is a Willam Daum Euler fonds at Library and Archives Canada.