Kanervo placed fifth in the 110 m hurdles at the 2011 European Junior Championships. He won his first senior-level medals at the Finnish championships in 2012, winning bronze indoors in the 60 m hurdles and gold outdoors in the 110 m hurdles. At the 2012 World Junior Championships in Barcelona he again competed in the 110 m hurdles, setting a national junior record (13.61/99 cm) in the semi-finals; in the final he ran 13.62 and placed fifth.