Wagner was part of the famous festival that celebrates his grandfather's operas for 57 years. He began working together with his brother Wieland in 1951, and took over sole leadership in 1966 when Wieland died.
"He had dedicated all his life to the heritage of his famous grandfather," a statement on the festival website read.
The former festival director, who retired in 2008, made a point of hiring innovative composers such as Daniel Barenboim, James Levine, Pierre Boulez und Christian Thielemann, and provocative directors like Götz Friedrich, Heiner Müller, Christoph Schlingensief, and Patrice Chereau.
The question of who would take over after his retirement was fraught with drama. Wagner initially favoured his second wife Gudrun and their daughter Katharina, but the festival foundation board chose his daughter from his first marriage, Eva Wagner-Pasquier.
Wagner was unhappy with the choice and refused to retire, but after the sudden death of his wife Gudrun, half-sisters Katharina and Eva were chosen to run the festival together and Wagner retired peacefully.
The Bayreuth festival, dedicated to the works of Richard Wagner including "Parsifal" and the "Ring" cycle, takes place every year in the Bavarian city from which it takes its name.