Following his training at the Royal Academy of Fine Arts in Antwerp, Joostens experimented with various artistic styles. In 1917 he had his first exhibition. He founded the group Bond zonder Gezegeld Papier (Bond without sealed paper), with van Ostaijen and the Jespers brothers and discovered Cubism. In 1920 he collaborated with Jos Léonard and the Jespers and founded the journal Novy. He travelled to Paris and moved to Neo-gothic style. In 1937 he published a number of his iconic ‘photomontages’. After WWII he produced the series Poezeloezen. He died in 1960 in Antwerp.