[1] In 1980, he was the winner of the International Dvorák Competition in Karlovy Vary.
[1] In 2000, he performed the role of Pluto in the first modern revival of Giovanni Legrenzi's La divisione del mondo at the Schwetzingen Festival.
[2] In the 2006/07 season Friedrich performed the role of Publio in Mozart's La clemenza di Tito in a production by Ursel and Karl-Ernst Herrmann [de], and under the musical direction of De Marchi at the Estates Theatre in Prague.
[2] He worked with Norman Shetler in various lied projects, including Franz Schubert, Felix Mendelssohn and Carl Loewe).
[6][7] In 2002, Friedrich was one of the co-founders of the Kerll-Rosenmüller Festival, which was held annually from 2002 to 2006 to promote the musical heritage of the Baroque composers Johann Caspar Kerll, Johann Rosenmüller and Sebastian Knüpfer.