Philip Herbert grew up amid the grandeur of Wilton House in Wiltshire, the eldest son from his father's second marriage to Katherine Villiers. Baptized on January 5, 1652/53, his early life was shaped by privilege and aristocratic legacy. At age 22, he inherited the titles of 7th Earl of Pembroke and 4th Earl of Montgomery on July 8, 1674, following the death of his half-brother. Later that same year, on December 17, he married Henrietta de Kéroualle, sister to the king’s mistress, further cementing his connection to the royal court. The pair had one daughter, Charlotte, who would continue the family line through subsequent noble marriages. Philip was also made a Knight of the Bath and held key regional offices such as Custos Rotulorum and Lord Lieutenant.

Herbert’s descent into real violence began in earnest in early 1678. After being briefly detained in the Tower of London for blasphemy and other offensive conduct, he returned to his violent ways almost immediately. On February 5, he struck Philip Rycault in the Strand, prompting a peace bond. Days later, Herbert kicked to death Nathaniel Cony in a tavern for no discernible reason. Although indicted for murder by a Middlesex grand jury, he was tried by his peers on April 4, 1678, and found guilty only of manslaughter. Leveraging his privilege as a peer —a once-only escape clause—he was released after paying fees, with a stern warning from the presiding judge that such leniency would not be extended again.

Nine months later, Sir Edmund Berry Godfrey, the grand jury foreman who had indicted Herbert, turned up dead, impaled on his own sword in what became one of the era’s greatest mysteries—the Popish Plot. Writers John Dickson Carr and Hugh Ross Williamson, along with historian J.P. Kenyon, have all suggested Herbert as the most likely suspect, citing motive and opportunity.

Herbert’s final act of violence occurred on August 18, 1680, when he killed William Smeeth, an officer of the watch, after a night of drinking at Turnham Green. Indicted again in June 1681, he was denied the peerage immunity this time. He fled briefly but then benefitted from a royal pardon secured by a petition from 24 peers.

Philip Herbert died at age 30 on August 29, 1683. He was buried at Salisbury Cathedral. His brother Thomas inherited the estates and titles and sought permission to sell parts of the estate to support Herbert’s daughter.