Childeric's father is recorded by several sources including Gregory of Tours to have been Merovech, whose name is the basis of the Merovingian dynasty. Gregory reports that Merovech was reputed by some to be a descendant of Chlodio who was an earlier Frankish king who had conquered Roman Gaulish areas in the Silva Carbonaria, then in Tournai, Cambrai and as far south as the Somme. This is roughly the definition of the Roman province of Belgica Secunda (approximately the "Belgium" defined by Julius Caesar centuries earlier, the region stretching from north of Paris to the Flemish coast) and later a letter of Saint Remigius to Childeric's son Clovis I implies that Childeric had been the administrative chief of this Roman province.
In records from Childeric's own lifetime, he is mainly associated with the Roman military actions around the Loire river, where he appears in records involving the Gallo-Roman general Aegidius. According to Gregory of Tours, Childeric was exiled at some point, the reason being given as Frankish unhappiness with Childeric's debauchery and seduction of the daughters of his subjects. Childeric spent eight years in exile in "Thuringia" waiting to make a return. In the meantime, according to Gregory, Aegidius himself took up the title of king of the Franks. Upon his return Childeric was joined by the wife of his host, Queen Basina, who bore Childeric his son Clovis.
Guy Halsall connects the story to Roman politics, Aegidius being an appointee of Majorian:
- "Although this is only one interpretation of the fragmentary sources, an eight-year period ending with Aegidius' death would allow us to associate Childeric's expulsion with Majorian's accession and appointment of Aegidius."
- "Majorian's commander on the Loire, Aegidius, refused to accept Severus as emperor. It is possible that, to legitimise his position, he took the title king of the Franks."
Halsall (p.269) speculates that Childeric probably began a Roman military career in the service of Flavius Aetius who defeated Attila in Gaul, and he points out that much of his military career appears to have played out far from the Frankish homelands. Ulrich Nonn (map p.37, and pp.99-100), following his teacher Eugen Ewig, believes that the exile story reflects a real sequence of events whereby Childeric was a leader of "Salian" or "Belgian" Franks based in the Romanized areas conquered by Chlodio, who were allies under the lordship of Aegidius, but eventually able to take over his power when he and his imperial patron died. (Childeric's son Clovis I later fought Aegidius' son Syagrius who was remembered as a King of Romans, and who had control of Soissons in the south of Belgica Secunda.)
In a passage normally considered to have come from a lost collection of Annals, Gregory (II.18) gives a sequence of events which are very difficult to interpret. In 463 Childeric and Aegidius successfully repelled the Visigoths of Theoderic II from Orleans on the Loire. After the death of Aegidius soon after, Childeric and a Comes ("count") Paul are recorded defending the Loire region from Saxon raiders, who were possibly coordinating with the Goths now under Euric. Childeric and Paul fought Saxons under the command of a leader named "Adovacrius" (sometimes given by modern authors in either an Anglo-Saxon spelling form, Eadwacer, or in a spelling the same as used for his contemporary the future King of Italy Odoacer, with whom he is sometimes equated). The origin of these "Saxons" is however unclear, and they are described as being based upon islands somewhere in the region.
Soon after this passage, Gregory of Tours (II.19) reports that Childeric coordinated with "Odovacrius", this time normally assumed to be the King of Italy, against Allemani who had entered Italy. While some authors interpret these Allemani to be Alans, a people established in the Loire region in this period, there is no consensus on this, because the reference in this case is not apparently to events near the Loire.