In 1992, he founded the Tsu Ensemble Chorus, officially known as "Vocal Ensemble 《EST》", which he still conducts. He also conducts the Yachimata Choir and, on occasion, the Ritsumeikan University Choir.
He specializes in church choir music from European Renaissance and has received numerous awards for his work both in Europe and his native Japan. In 2007 he was included in the book "Who's Who in Choral Music".
When not conducting, Masao Mukai teaches high school Math. In recent years he taught at Ujiyamada High School in the city of Ise, Mie Prefecture where, as conductor of the chorus club, he led the school to numerous appearances in the final chorus competition at the national level and won first place twice. He now teaches at Matsusaka Technical High School. He also occasionally gives lectures and acts as a judge at choral competitions.
