Benielli studied teaching in Mendoza. In 1897, he became a professor at the "Escuela Normal de Profesores "Mariano Acosta"" in the Balvanera district of Buenos Aires. Later, he was posted to a teaching position in Venado Tuerto, Santa Fe Province. While there, he made friends with Cayetano Alberto Silva, a violinist and composer. As a result, in April 1907 he wrote the lyrics to the "San Lorenzo March" (composed by Silva in 1901). This march (his most famous work), commemorates the Battle of San Lorenzo and memorializes the heroic actions of sergeant Juan Bautista Cabral. He also wrote lyrics for marches commemorating the battles of Tuyutí and Curupaytí (both also with music by Silva) and the "Hymn to San Martín" (set to the music of the "Triumphal March" from the opera "Aida" by Verdi). He is also the author of a book; "Menudencias Lingüísticas" (Linguistic Trifles).