He was a disciple of his father, Italian painter Patricio Cajés, who had moved to Madrid to work on the monastery of El Escorial. He is thought to have spent time in Rome around 1595, where he would have taken part in the birth of Caravaggio's naturalism, and he must have returned to Spain with a fondness for Tempesta's battle compositions, which Vicente Carducho's generation knew through prints and repeated continually as background for their scenes. His friendship with painter Juan Pantoja de la Cruz is documented, and he even appears in Pantoja's testament, although he is listed there as an ivory sculptor, rather than a painter. In 1601 and 1604, he and his father were contracted together, but in 1602 he was already being contracted alone, as well. In 1604, he received a royal commission to paint copies of Antonio Correggio's “Rape of Ganymede” and “The Fable of Leda”, both at the Museo del Prado. In 1608, he worked on the decoration of the El Pardo Palace, and in 1612 he was appointed king's painter. In 1628, he requested the post of chamber usher, which was approved by the monarch but never carried out. His figure was praised on multiple occasions by his period's writers, including his close friend, Lope de Vega. Among his most outstanding works are the frescoes he painted in 1615 for the shrine of Toledo Cathedral. These works were one of many collaborations with Vicente Carducho, with whom he also painted the main altarpiece for the monastery of Guadalupe (Caceres) in 1618, and the altarpiece for the church in Algete (Madrid) in 1619. Cajes also contributed to the decoration of the Buen Retiro Palace's Hall of Realms with a “Recovery of San Juan de Puerto Rico”, which he died before completing. His disciples, Antonio Puga and Luis Fernández finished the work. Along with Vicente Carducho and Angelo Nardi, Cajés fought for recognition of the dignity of painting, demanding an exemption from taxes that equated painters with other craftsmen organized in guilds. Following his death, he was buried in the monastery church of San Felipe el Real, where he had painted the altarpiece in 1605. Along with its archaic echoes of the late El Escorial school— attenuated by the memory of Bartolomé Carducho—his style emphasizes soft forms that may have drawn on his experience copying Correggio, which distinguishes him from the rougher drawing style of his contemporaries. That characteristic persisted in the works of his disciple, Antonio de Lanchares. He was particularly interested in the use of light that helped create that morbid and intimate sensation visible in his Virgin with the Christ Child and Angels (Prado) and indicative of a knowledge of chiaroscuro attuned to the international panorama of his time and to the work of Juan Bautista Maíno (Sánchez del Peral, J. R., Enciclopedia M.N.P, vol. II, pp. 590-591).