Seitz was a native of Munich, Bavaria, son of Johann Baptist Seitz. He studied at the Munich Academy of Art under Joseph Schlotthauer and afterwards worked independently as a lithographer and engraver. In 1848 he took over the artistic direction of the satirical newspaper Leuchtkugeln. From 1855 he was the costume director of the Munich Hoftheater. In 1858 he was appointed professor at the Academy of Art.
In 1869 he was made artistic director of the Court Theatre (Hofbühne) and director of scenery at the Residenz Theatre, Munich. In 1876 he retired and was made an honorary Member of the Academy of Art.
Franz von Seitz was buried in the Alter Südfriedhof in Munich.
