Born in Cesky Krumlov, Bohemia (now in the Czech Republic), the artist was accepted as a student at the Akademie der Bildenden Kunste, Vienna, in 1756, where he studied for about ten years. In 1768 he was commissioned by Empress Maria Theresa to travel to Italy to paint portraits of the nobility of Milan, Parma and Florence; he became a member of the Accademia di Belle Arti in Florence in 1769. In 1772 he was appointed deputy head of the Vienna Gemäldegalerie and in 1776 became painter to the Imperial court. He was granted full membership of the Akademie in Vienna that same year, submitting the Portrait of a Man Aged 104 from Bohemia (Vienna, Akademie der Bildenden Kunst) on his admission.
In the 1780s Hickel was one of the most sought-after portrait painters in Vienna. He is believed to have painted more than 3,000 portraits, including those of the Austrian Imperial family (for example the Portrait of the Emperor Joseph II sold, Christie's, London, 8 July 1999, lot 213 [£25,000]), Pope Pius VI and King Ferdinand IV and Queen Maria Carolina of Naples, as well as members of the nobility, middle classes and actors at the Hofburg theatre. Engravings after these untraced portraits, for example by Johann Peter Pichler (1766-1807), reveal that his paintings follow the late Baroque tradition of Martin van Meytens (1695-1770).