Sir Lamorak was a younger son of King Pellinore of Listinoise. His epithet means ‘of Wales’ but at this period refers to the whole of Britain. He was known as the third greatest Knight of the Round Table, following Sirs Tristram and Lancelot. On a number of occasions he is recorded as having beaten over thirty knights in a tournament: notably at Sir Gareth’s wedding feast and when travelling with Sir Driant in the Cornish lands of King Mark. After the latter encounter, the troublesome monarch had Sir Tristram fight the exhausted Lamorak. The young King of Lyonesse reluctantly agreed and managed to dismount his opponent, but he refused to dishonour himself further by carrying on. Lamorak was extremely put out by Tristram's courtesy and was still fuming when he encountered a messenger bearing Morgan le Fay's infidelity-seeking drinking horn to King Arthur's Court. He forced the page to carry the prize to King Mark's Court instead, an act which almost resulted in the exposure of Tristram and La Beale Isolde's affair, as well as those of ninety other ladies. Tristram was understandably angry.

The two soon settled their differences, however, when shipwrecked together on the Isle of Servage. Conspiracy seems to have brought them together, as they plotted the downfall of Sir Nabon le Noir, a mutual enemy. Shortly afterward, they attended his tournament and Tristram killed him in battle. However, the truce was forgotten when Tristram was again shipwrecked - this time near the Castle Perilous in North Wales - and the two fought for hours before being reconciled once more.

Further combat followed for Lamorak as he encountered Sir Frol of the Out Isles, Sir Belliance le Orgulus, Sir Lancelot and Sir Gawain. Some meetings were more friendly than others. His battle with Meliagrant concerned an argument over Queen Guinevere was more beautiful than Queen Morgause; and revealed a passion which was to be Lamorak’s undoing.

Lamorak became Morgause’s lover, despite the fact that his father had killed her husband, King Lot of Orkney. The Queen’s sons suspected a liaison and Sir Gaheris eventually discovered the two in bed together. He sliced off his mother’s head in a fit of rage, but Lamorak escaped. He complained bitterly to King Arthur concerning his treatment at the Surluse Tournament and the monarch promised to protect him. However, in the end, he was slain by the sons of Lot.

It is just possible that this character's name was inspired by King Llywarch Hen of South Rheged. He is sometimes said to have been a warrior at Arthur's Court, despite the fact that he wasn't born until about the time of the great monarch's death.