His parents were Johann IV, Count of Katzenelnbogen (younger line) and Anne of Katzenelnbogen (older line), who merged the two lines of the family back together in 1402.

Philip married on 24 February 1422 in Darmstadt Anna of Württemberg (1408–1471),[1] daughter of Eberhard IV "the Younger" of Württemberg.

In 1456, he obtained from the Pope a divorce a mensa et thoro.

[2] In 1474 Philip married Anne of Nassau-Siegen.

The County of Katzenelnbogen fell to the Landgraviate of Hesse, which was ruled at the time by Philipp's son-in-law Henry III of Hesse in Marburg, Henry having bought off the inheritance rights of Philipp's granddaughter Ottilie.