He coached Harry Houdini as a teenager in running at the Pastime Athletic Club. He remained a friend to Houdini and exposed many fraudulent mediums throughout his career. Rinn was notable for describing the tricks of physical mediums.
He exposed the billet reading of Bert Reese.
Science writer Martin Gardner has noted that Rinn had provided "good description of one of Reese"s billet-reading performances, with an explanation of how he did lieutenant"
Rinn would offer huge amounts of money, up to $10,000 to anyone who could demonstrate a psychic event. However, as nobody ever did, the money went unclaimed.
Rinn"s work in debunking psychic phenomena has been praised by psychologists in the field of anomalistic psychology. Rinn became disillusioned with the American Society for Psychical Research as he believed they had failed to expose cases of psychic fraud so in 1905 he formed a skeptical group known as the Notable skeptical members who were also magicians included Winfield South. Davis and James L. Kellogg.
In January, 1910 a series of séance sittings were held in the physics laboratory at Columbia University with the medium Eusapia Palladino.
Scientists such as Robert West. Wood and Edmund Beecher Wilson attended. Davis, Kellogg, Rinn and John West. Sargent, a past-president of the Society of American Magicians were present in the last séance sittings in April. They discovered that Palladino had freed her left foot to perform the phenomena.
Rinn gave a full account of fraudulent behavior observed in a séance of Palladino.
He was a former one year member of the American Society for Psychical Research and a lifelong inquirer into psychic matters. He was a member of the Society of American Magicians.