Mr. Mostardo founded the Festival Chorus at William Rainey Harper College in Palatine, Illinois, starting with 60 members in 1965 and by 1997 growing to over 150 members at the time of his retirement. The Festival Chorus achieved particular distinction by attracting the top vocal and instrumental solo artists in the greater Chicago area, performing with the chorus to audiences averaging over 2,000 each concert. Additionally the chorus traveled extensively throughout Europe performing in many of the great cathedrals and music festivals in Vienna, Salzburg, Zagreb, Dubrovnik, and Coventry, England, and in the countries of Scandinavia. A highlight of his musical career included a guest performance with the Festival Chorus in St. Peter's Basilica in Rome, in 1986, which was broadcast on Italian radio and television. The Festival Chorus was one of only seven choruses worldwide invited to perform in the Vatican up to that time. He is the founder, music director, and conductor of San Diego Festival Chorus.
Mr. Mostardo lives in Spring Valley, California, with his wife Greta, also a member of San Diego Festival Chorus and an accomplished musician.