In this article I use new archival and elite interview data to improve our knowledge of how the Canadian Multiculturalism Act came into existence. I show why some Canadians began to seek such an act, why political parties promised an act and how this act was created. The evidence in this article will also correct claims that scholars often make about this act and the policy of multiculturalism that it contains. This evidence also improves our knowledge of why the policy of multiculturalism in this legislation does what few scholars would expect. This is because scholars often claim that policies of multiculturalism are used to “repudiate” and remove understandings of a country. But my evidence helps to show why the policy of multiculturalism in this act promotes understandings of a country. Scholars also claim that policies of multiculturalism can be divisive if they are unaccompanied by nation-building policies. But my evidence helps to show why the policy of multiculturalism in this legislation was designed to be a nation-building policy.