[1] After the foundation of the Irish National Land League in October 1879 he moved to Dublin as a legal secretary in head office.

Doris was chairman of Westport UDC 1899-1910 and vice-chairman of Mayo County Council 1900–08, speaking at the latter's first meeting on 22 April 1899.

Like the rest of the Irish Party, William Doris supported the United Kingdom during the First World War, and this led to alienation from his brother Patrick.

Doris was first recorded in the House of Commons of the United Kingdom, Westminster, on 15 March 1910 on the topic of Old Age Pensions (Ireland).

'...the handing over of the lives and properties, and the social, political, commercial and religious interests of 350,000 Catholics and Nationalists in the North to the tender mercies of an Orange parliament in Belfast has been the direct result of the destruction of the Irish Party in 1918.