 After studying at the Naples Conservatory under Beniamino Cesi (and composition under Paolo Serrao), he began teaching piano at his alma mater in 1887, deputizing for Cesi as pianoforte professor, and succeeded him in 1897.As a pianist, Longo often played in chamber ensemble with the Ferni Quartet, and with the Quartetto Napoletano (with Cantani, Parmiciano, Scarano and Viterbini).He founded various musical institutions in Naples, and gained a high reputation as a concert pianist.