From the late 1970s, he taught acting at the American Repertory Company, where he focused intensely on each individual student, as he never let the class get larger than 12 students at a time. He wanted to have the luxury of giving anywhere from 15 minutes, and sometimes even up to one hour, of feedback and critiques. This was highly effective, ensuring the next time that student came to class and put up his work, it was taken to the next level. Tupou trained Eric Roberts, Ernie Reyes Jr., Calvin Levels, Santino Ramos, Jerri Manthey, Kath Soucie, and Arash Dibazar, among others. He died of pancreatic cancer in 2004.