Donnchadh's career is not well documented in the surviving sources. Charters provide a little information about some of his activities, but overall their usefulness is limited; this is because no charter-collections (called cartularies) from the Gaelic south-west have survived the Middle Ages, and the only surviving charters relevant to Donnchadh's career come from the heavily Normanised English-speaking area to the east. Principally, the relevant charters record his acts of patronage towards religious houses, but incidental details mentioned in the body of these texts and the witness lists subscribed to them are useful for other matters.
Some English government records describe his activities in relation to Ireland, and occasional chronicle entries from England and the English-speaking regions of what became south-eastern Scotland record other important details. Aside from the Chronicle of Melrose, the most significant of these sources are the works of Roger of Hoveden, and the material preserved in the writings of John of Fordun and Walter Bower.
Roger of Hoveden wrote two important works: the Gesta Henrici II ("Deeds of Henry II", alternatively titled Gesta Henrici et Ricardi, "Deeds of Henry and Richard") and the Chronica, the latter a re-worked and supplemented version of the former. These works are the most important and valuable sources for Scottish history in the late 12th century. The Gesta Henrici II covers the period from 1169 to April 1192, and the Chronica covers events until 1201. Roger of Hoveden is particularly important in relation to what is now south-western Scotland, the land of the Gall-Gaidhil. He served as an emissary in the region in 1174 on behalf of the English monarch, and thus his account of, for example, the approach of Donnchadh's father Gille-Brighde towards the English king comes from a witness. Historians rely on Roger's writings for a number of important details about Donnchadh's life: that Gille-Brighde handed Donnchadh over as a hostage to Henry II under the care of Hugh de Morwic, Sheriff of Cumberland; that Donnchcadh married the daughter of Alan fitz Walter under protest from the Scottish king; and that Donnchadh fought a battle in Ireland in 1197 assisting John de Courcy, Prince of Ulster.
Another important chronicle source is the material preserved in John of Fordun's Chronica gentis Scottorum ("Chronicle of the Scottish people") and Walter Bower's Scotichronicon. John of Fordun's work, which survives on its own, was incorporated in the following century into the work of Bower. Fordun's Chronica was written and compiled between 1384 and August 1387. Despite the apparently late date, Scottish textual historian Dauvit Broun has shown that Fordun's work in fact consists of two earlier pieces, Gesta Annalia I and Gesta Annalia II, the former written before April 1285 and covering the period from King Máel Coluim mac Donnchada (Malcolm III, died 1093) to 2 February 1285. Gesta Annalia I appears to have been based on an even earlier text, about the descendants of Saint Margaret of Scotland, produced at Dunfermline Abbey. Thus material from these works concerning the late 12th- and early 13th-century Gall-Gaidhil may represent, despite the apparent late date, reliable contemporary or near-contemporary accounts.