John Tracy, whose name is on a Los Angeles clinic for hearing-impaired children encouraged Marsters to become an orthodontist, and in 1954, after studies at USC, he began his Pasadena practice. Soon after that, he married Alice Amelia Dorsey, the director of the clinic at John Tracy Clinic's preschool. Marsters had three children—James Marsters Jr., a chemist; Jean Marsters, a doctor; and Guy Marsters, a musician.