His family moved to Kassa when he was still very young and he displayed an early talent for drawing. He began his studies in 1861 with Hermann Anschutz and Johann Georg Hiltensperger (1806–1890). From 1865 to 1869, he studied with Karl von Piloty.

He achieved international success in 1870 when he won the Hungarian national competition for historical painting with his depiction of King Stephen’s baptism. He then assisted Piloty with the frescoes at the Maximilianeum and the Rathaus in Munich and illustrated books by the great German writer, Friedrich Schiller. King Ludwig II of Bavaria gave him several commissions.

He was named a Professor at the Academy of Fine Arts, Munich, in 1875. Soon after, he built a home in Ambach on Lake Starnberg; designed by his brother Béla. In 1883, he returned to Hungary, where he continued to be an art teacher. One of his most distinguished pupils was the Swiss-born American painter Adolfo Müller-Ury. Benczúr was later a favorite among the Hungarian upper-class, painting numerous portraits of kings and aristocrats. He also created some religious works; notably altarpieces for St. Stephen’s Basilica and Buda Castle.

He was an honorary member of the Hungarian Academy of Sciences. Streets have been named after him in Balassagyarmat, Balatonkenese, Berettyóújfalu, Bonyhád, Budapest, Debrecen, Jászberény, Komló, Pécs, Szabadszállás, Szeged and Košice. His daughters Olga (1875–1962) and Ida (1876–1970) also became well-known artists.