Calixa LavallÃ e , ( born Quebec , 28 December 1842 ; died Boston , 21 January , 1891 ) , was a Canadian-American composer . Calixa LavallÃ e , ( December 28 , 1842 -- January 21 , 1891 ) , born Calixte LavallÃ e , was a French-Canadian-American musician who composed the music for O Canada , which officially became the national anthem of Canada in 1980 .