Guglielmo plays with several orchestras, including Trieste’s Teatro Verdi Orchestra, the Orchestra of Teatro alla Scala in Milano, the Orchestra Filarmonica della Scala and the Orchestra Filarmonica Toscanini, under conductors such as A. Pappano, C. Abbado, J. E. Gardiner, D. Gatti, V. Gergiev, E. Inbal, D. Kytajenko, L. Maazel, K. Masur, D. Matheuz, Z. Metha, D. Oren, G. Pretre and S. Bichkov; Guglielmo has also an important soloist career, as well as an intense chamber music activity.
Founding member of the Italian Wonderbrass Quintet and of the Kalamos Wind Quintet, Guglielmo has obtained accolades in both Europe and North America. Guglielmo performed the World Premiere of F. Perez Tedesco’s concert for horn and strings composed for him at the Festival “Suoni d’aria d’alta quota”. Together with Federico Lovato, Guglielmo Pellarin recorded the monograph “French Music for horn and piano”, which includes the first release of the sonata for french horn and piano by J. M. Damase.