Pepin first appears in 834 as a count to the north of the Seine and then appears as same again in 840. In that year, he supported Lothair I against Louis the Pious.
Pepin's wife is unknown, she has been spuriously called "Rothaide de Bobbio". His heir inherited much Nibelungid territory and so historian K. F. Werner hypothesized a marriage to a daughter of Theodoric Nibelung. Their children were:
Bernard (c. 844 – after 893), count of Laon
Gerberge (born c. 854)
Pepin (c. 846–893), count of Senlis and lord of Valois (877–893)