His father named him after the character King Lisuart of the Amadis de Gaula stories.
Born in Bragança, he served as personal secretary to the Portuguese ambassador in France, and composed, during two voyages to Paris (1540 and 1546), a chivalric romance called Palmerin d’Angleterre (Palmeirim de Inglaterra; Palmerin of England), a "spin-off" of the popular Amadis de Gaula series.
Specifically, he has written important and influential works on Don Quixote, the chansons de geste, the medieval novel (notably Amadis de Gaula), the troubadours, courtly love, the history of Catalan literature, and the social phenomenon of the knight errant.
Exemplary work, such as the English Le Morte d'Arthur by Sir Thomas Malory (c. 1408–1471), the Catalan Tirant lo Blanch, and the Spanish or Portuguese Amadis de Gaula (1508), spawned many imitators, and the genre was popularly well-received, producing such masterpiece of Renaissance poetry as Ludovico Ariosto's Orlando furioso and Torquato Tasso's Gerusalemme Liberata and other 16th-century literary works in the romance genre.
This type of novel was best personified in the 1508 version of João de Lobeira's Amadis de Gaula by Garci Rodríguez de Montalvo, the 1541 Cronica do famoso e muito esforçado cavalleiro Palmeirim d´Inglaterra by Francisco de Moraes, and the 1522 Crónica do Imperador Clarimundo, by João de Barros.
In number 230, Lobeira uses the same ritournelle that Oriana sings in Amadis de Gaula, and this has led to his being generally considered by modern supporters of the Portuguese case to have been the author of the romance, in preference to Vasco de Lobeira, to whom the prose original was formerly ascribed.
It was through her that he was exposed to tales of knight errantry like Don Quixote, Amadis de Gaula, and El Cid.