As part of his alliance with France, Philip married Maria of Savoy, daughter of Amadeus IX of Savoy, and one of the nieces of Louis XI, King of France, around 1476 or 1478. With Philip's death, the male line of the Hachberg-Sausenberg family died out. Philip's father, Rudolf IV, had begun negotiations with the senior line of the House of Zahringen, which ruled the margraviate of Baden on the possibility of an inheritance treaty. Philip continued the negotiations with Christopher I, Margrave of Baden and on 31 August 1490, they came to an agreement on reciprocal inheritance. The treaty is known as the "Rötteln Match". The background of this treaty was that Christopher I intended his son and heir Philip I to marry Joan, the heiress of Hachberg-Sausenberg. This marriage did not materialize, due to political pressure from the French king. His daughter, Johanna von Hachberg-Sausenberg, became Countess of Neuchâtel after her father's death in 1503, while Christopher obtained Sausenberg, Rötteln, Badenweiler and Schopfheim. In 1504, she married Louis d'Orléans-Longueville who, not yet having inherited his father's dukedom of Longueville, became known, jure uxoris, as the Marquis de Rothelin . Joan and the House of Orléans-Longueville contested the Rötteln treaty and they tried to rally support for their case from the Swiss cantons of Solothurn, Luzern, Fribourg and Bern. The dispute was settled in 1581, with the House of Baden paying to the House of Orléans-Longueville, but securing for Christopher's great-grandson Margrave Georg Friedrich of Baden-Durlach Sausenberg, Rötteln and Badenweiller in 1584.
In 1474 and 1475, he participated in the Burgundian sieges of Neuss and Nancy; in 1476 he fought with Charles the Bold in the battles of Grandson and Murten. After the defeat of Charles the Bold in the 1477 Battle of Nancy, Margrave Philip turned away from Burgundy and sided with France, in an effort to avoid losing his Burgundian possessions. In 1484, Philip participated in the coronation of the French King Charles VIII in Reims. The king sent Philip to Switzerland as a negotiator. Philip was appointed Marshal of Burgundy and Philip de Hochberg, as he was called in France, had a strong influence on politics there. In 1484, he was appointed Chamberlain and in 1489, he became a member of the Royal Council of France. In 1499, he fought on the French side, while his subjects from Rötteln fought in the Imperial army. In 1494 Philip inaugurated a new mansion at his Rötteln Castle. The interior of the Palace at Neuchâtel is also attributed to him. He died in Montpellier, aged about 59.
