Although there are no records in the Guild of Saint Luke showing him as a pupil of Sebastian Vrancx, it is clear that he received his initial training from this painter. He subsequently joined the Guild as a master around 1612–1613. Like Vrancx, he specialised in battle scenes. Even though at the beginning of his career he produced small paintings depicting scenes of skirmishes and path robberies in a style similar to Vrancx’s, he soon transitioned to large paintings of historical sieges which, based on the 16th-century series of battlefields, had a great impact on the production of Flemish tapestries. Snayers’s paintings differ from those of Vrancx in terms of distribution of the composition. Whereas in Vrancx’s paintings the war occupies the centre of the scene, Snayers inverts this compositional device. Consequently, he directs the viewer’s attention towards the background of the landscape by employing a high viewpoint that elevates the horizon line and confers a topographical and precise representation of the war. In turn, this depiction simulates the unfolding of a map representing the event. The foregrounds (set on mounds in the terrain) of his paintings produce a contrast with the backgrounds (reflecting battles) and the area immediately in front of the viewer (where an anecdotal scene unfolds). The rich colouring of Vrancx’s work is replaced by more homogenous tones covering the entire canvas.
Although he was never the official painter to the Archdukes Albert and Isabella, evidence shows that he worked for the Infanta, whom he portrayed during a visit to the siege of Breda (Prado). Following the death of Isabella, he worked for Cardinal-Infante Ferdinand, who appointed him court painter, and later for Archduke Leopold Wilhelm. Due to his good relations with the political authorities his work was widely recognised, and his battle scenes and portraits were particularly appreciated by the military and the courtiers who were close to the Brussels court. Among these prominent figures were Ambrogio Spinola, Count of Bucquoy – of whom he produced numerous portraits – and the Marquess of Leganés, who owned, in addition to portraits, vast series of battlefields by Snayers on the Thirty Years’ War and similar to those preserved in the Museo del Prado. On the other hand, Snayers had artistic relationships with other painters including Van Dyck, whose portrait he painted (Alte Pinakothek in Munich), and Rubens, who selected him for the production of two canvases from the series on Henry IV (1628–1630). He was an artist of great prestige, renowned as a master of other battle scenes painters, including Adan Frans van der Meulen, who was his pupil beginning in 1646. In addition to the numerous battle scenes and illustrations of 17th-century European wars by Snayers, the Museo del Prado houses Mallard Hunters, an example of his activity as a painter of landscape, to which he actively dedicated himself in the 1640s (Pérez Preciado, J. J. in: E.M.N.P., 2006, tomo VI, pp. 2017-2018).