Ockeghem served three successive Kings over nearly 50 years: Charles VII (until the monarch's death in 1461, for which the Requiem may have been composed), Louis XI (1461-1483), and Charles VIII. As early as 1454, court registers record Ockeghem giving a songbook to the King personally; these refer to him as premier chapellain. Along with this prestigious title, Charles VII named Ockeghem to the powerful and lucrative post of Treasurer of the Abbey of St. Martin in Tours, the wealthy monastery of which the King was himself titular Abbot. Then, in 1464, Louis XI elevated him to be called Maistre de la chapelle de chant du roy; the distinguished singer and composer would hold all three titles until his death. In addition, he held benefice incomes such as a canonicate at Notre Dame in Paris (later exchanged for one at St. Benoit, Paris). He appears not to have traveled much, though in 1464 he visited Guillaume Dufay in Cambrai, and in 1470 journeyed to Spain. His will in 1484 endowed the chapter of St. Martin with his goods and income; this may have been in response to an illness. His death, however, (apparently in retirement) did not occur until 1497.
Ockeghem enjoyed a stellar reputation among contemporary musicians as well as his employers. He apparently knew Gilles Binchois, composer to the Burgundian Court, for whom he composed the lament Mort, tu as navré in 1460. In turn, Antoine Busnois, singer of the count of Charolais (soon to be Duke of Burgundy) honored Ockeghem with the motet In hydraulis in 1465-1467. Johannes Tinctoris, theorist and composer, called Ockeghem the first among all the most excellent composers of his time, and even Duke Galeazzo Maria Sforza of far-off Milan sought his assistance in the recruitment of singers. Upon Ockeghem's death, laments were composed by some of the greatest figures of his age, including poets (Guillaume Crétin and Jean Molinet), composer (Josquin Desprez, who's "Deploration sur la mort d'Ockeghem" is a masterpiece), and thinker (Erasmus of Rotterdam).
To modern ears, the music of Ockeghem is characterized by non-pulsative (irregular yet flowing) rhythms that are more the result of counterpoint, low velvety textures from the male choir and a subtle use of imitation. This imparts a mystical, revelatory and inspired quality, especially in the Masses. Ockeghem's "Missa prolationum" consists entirely of mensuration canons, combining the cerebral in organization with the emotional is expression. His "Missa mimi" is a highly characteristic masterpiece. Ockeghem also composed Motets and lovely two, three and four part Chansons.