The 47-year-old, uncle to Princes William and Harry, tied the knot with Canadian philanthropist Karen Gordon today in a private ceremony at the Spencer family home attended by close loved ones.
The grounds of the estate in Althorp, Northamptonshire became the final resting place of Diana after her death in a car accident back in 1997.
Earl Spencer announced his engagement to Gordon, founder of the Whole Child International charity, in February.
He has been married twice before, to former model Victoria Lockwood from 1989 to 1997 and Caroline Frued between 2001 and 2009. He has six children.
His charity-worker wife divorced from Hollywood producer Mark Gordon in 2003. The former couple have two daughters together.
Earl Spencer and Gordon were both in attendance at the wedding of Prince William and Kate Middleton in April.