Härö has been interested in film since his early childhood. He studied directing and screenwriting and graduated from the University of Art and Design in Helsinki in 1999. He had directed TV commercials and short films such as Maraton (1997) and Nattflykt (1999) before making his feature film debut Näkymätön Elina (As If I Didn't Exist, 2002), which brought him many awards at children’s film festivals and the Silver Bear at the Berlin Film Festival in 2003. He made a documentary Statisti (2003) and his second feature film Najbolja mama (Äideistä parhain, 2005).