The resonant reputation of William Butler Yeats (13 June 1865 – 28 Jan.1939) lies in his indisputable literary position as a prominent Modernist Irish poet and dramatist. Yet, Yeats formulated in his writings a new innovative literary trend; he mixed both traditional and modernist elements in them. The past and the present are juxtaposed professionally together. The Irish historical heritage, myths, legends, and folklore were inexhaustible fountain for him in order to write his Modernist masterpieces. He achieved many important targets by reviving all these ancient sources. He aimed to unite all the Irish people, strengthening their patriotism and nationalism, to attract the world's attention to the Irish dilemma, and to resist peacefully the British colonization. Other psychological motives directed him towards the mystery and the strangeness of these traditional sources as his occultism, mysticism, and spiritualism. This research paper tries to trace how Yeats presented a modernist fashioning of tradition in his poetic and dramatic writings or how he moulded a traditional essence within a modernist structure. An overview of some of Yeats' famous poetic and dramatic works is provided in a thematic and/or analytic study regarding the limits of the research paper; though some samples are inspected as detailed proved examples.