Mashayekhi studied under Roman Haubenstock-Ramati at the University of Music and Performing Arts, Vienna. In the 1990s he was music director of the Austrian new music ensemble "Wien 2001".
His works have been performed by Klangforum Wien (1992–95), Ensemble Work in Progress, Berlin (1993), Ensemble Zwischen Töne, Berlin (1997–2000), Savarian Symphony Orchestra (1997), Radio Symphony Orchestra, Vienna (1998), and the Tehran Symphony Orchestra (1998–2000).