He is also known as Lemaire-Poussin, due to his frequent close collaborations with Nicolas Poussin.
He studied under Claude Vignon before moving to Rome, where there is evidence for his presence dated to 1613.
Around 1636 Lemaire took part in the decorative scheme commissioned by Philip IV of Spain for his Buen Retiro palace - Lemaire proposed a scholarly architectural classical landscape.
He returned to Paris in 1639 and re-allied with Poussin in 1640, becoming his main assistant in the decorative scheme in the Grande Galerie of the Louvre.
He was made guardian of the king's paintings at the Louvre and the Tuileries, at the suggestion of François Sublet de Noyers.