Frelinghuysen was born in New York City to Peter Frelinghuysen Jr., a New Jersey politician and Beatrice Sterling Procter, an heir to the Procter & Gamble fortune [REF].
His father, Peter Frelinghuysen, Jr., served as the U.S. Representative from New Jersey's 5th congressional district from 1953 to 1975, representing much of the same area Rodney does today.