Reinhard IV was born the son of Philipp I, Count of Hanau-Münzenberg and his wife, Countess Adriana of Nassau-Dillenburg (1449–1477). From 1496 to 1500, Reinhard IV acted as co-ruler alongside his father who was already disabled by old age.
He served as co-regent from 1496 onwards. His godfather was Prince-abbot Johann II of Henneberg-Schleusingen of the Fulda monastery. Reinhard IV made several journeys in his youth: in 1493 to the Palatine court at Heidelberg and in 1495 to the Diet of Worms.
He was the first count to use the name Hanau-Münzenberg, to distinguish his line from his relatives in Hanau-Lichtenberg.
The two lines had existed since the county was divided between Philipp the Elder and Philipp the Younger in 1458. Reinhard also added the arms of the Lordship of Münzenberg to his coat of arms.
In 1500, Reinhard exchanged some territories with the County of Isenburg, giving them Offenbach am Main and his share of Bracht and received the village of Bischofsheim (now part of Maintal) in return, thereby ending a protracted conflict between the two neighboring rulers. In 1503, he exchanged half the village of Trais (now part of Münzenberg) for the share in Seckbach held by the Counts of Solms.
In 1504, he purchased the other shares in Seckbach from their respective owners: the Schelme von Bergen family, the Farchen of Heidelberg family and the Glauburg family in Frankfurt.
The County of Hanau-Münzenberg suffered badly during the Landshut War of Succession in 1504, from the Hessian troops passing through the county and from the Hessian occupation of Bad Homburg, which Hanau had purchased in 1487 for 19000guilders. This issue was mediated by Emperor Charles V at the Diet of Worms in 1521. Hesse was allowed to keep Homburg, but had to reimburse Hanau with 12000guilders.
In 1505, Emperor Maximilian I appointed Reinhard IV as his councillor.
Reinhard IV was involved in several other disputes about his rights and his policies. The Lords of Hutten joined the resulting controversy, claiming the raid had happened on their territory.
Reinhard IV died on 30 January 1512 and was buried in the choir of Saint
