In his poetry, MacLean juxtaposed traditional Gaelic elements with mainstream European elements, frequently comparing the Highland Clearances with contemporary events, especially the Spanish Civil War. His work was a unique fusion of traditional and modern elements that has been credited with restoring Gaelic tradition to its proper place and reinvigorating and modernizing the Gaelic language. Although his most influential works, "Dàin do Eimhir" and "An Cuilthionn", were published in 1943, MacLean did not become well known until the 1970s, when his works were published in English translation. His later poem "Hallaig", published 1954, achieved "cult status" outside Gaelic-speaking circles for its supernatural representation of a village depopulated in the Highland Clearances and came to represent all Scottish Gaelic poetry in the English-speaking imagination.