He served on the Board of Directors of RCA and a listing of his professional colleagues and society friends reads like a "Who’s Who " of the rich and famous. Aside from his inherited wealth, his inventions brought Hammond an additional fortune. Between the years 1926 and 1929, he built a castle (including a drawbridge) which became his home, laboratory, and a showplace for his collection of Roman, medieval, and Renaissance artifacts. Hammond was also interested in the mechanism and workings of the pipe organ, and had a huge organ installed in the castle's Great Hall. Famous organists, including Richard Ellsasser and Virgil Fox, performed and made commercial recordings on this instrument, unfortunately no longer in operating condition (2015). Overlooking Gloucester Harbor in the North Shore region of Massachusetts, Hammond Castle is now a museum which offers self-guided tours throughout half the year and hosts fundraising events on a regular basis.