He was a member of the Merovingian dynasty, and was installed by Charles Martel, a contender for the office of mayor of the palace, in opposition to Chilperic II, whose rule was thereby restricted to Neustria.

[2] Chlothar was made king at the instigation of Charles Martel following his victory over the forces of Chilperic II and the mayor of the palace, Ragamfred, at the Battle of Vincy on 21 March 717.

The creation of a rival king in Chlothar IV served two goals: it legitimised Charles as mayor of the palace, an office which he claimed as an inheritance from his father, Pippin of Herstal, and it expanded his military resources by allowing him to raise a larger army through royal summons and the royal power to command.

In early 718, Charles led an army in Chlothar's name against the Neustrians and Aquitanians, whom he defeated at the Battle of Soissons, forcing Chilperic II to flee to Aquitaine and Duke Odo's protection.

[2][3][1] Charles's pursuit of Chilperic, which culminated in a negotiated settlement with Odo for the king's return, was probably required by the sudden death of Chlothar IV.