He was a head coach of Polish volleyball team Skra Bełchatów (2006-2009). In 2009-2010 he was a head coach of the Poland men's national volleyball team. In September 2009 Poland led by Castellani won title of the European Champion 2009 in Izmir, Turkey. He received a state award granted by the Polish President Lech Kaczyński – Officer's Cross of Polonia Restituta "for outstanding contribution to the development of Polish sport". He was dismissed before the end of his contract after an unsatisfactory result in the World Championship 2010 in Italy. In season 2012/2013 he worked with Polish club ZAKSA Kędzierzyn-Koźle. In May 2015 he went to Italian club Sir Safety Perugia. After one season in Belgian club Noliko Maaseik he moved to Brazilian Funvic Taubaté in May 2017. He was replaced by Renan Dal Zotto as a head coach of Funvic Taubaté in 2019.