In December 2007, he joined Sampdoria for a trial, and was shortly after invited by Fulham on the same basis.
In June 2010, he signed a three-year contract with Ekstraklasa side Górnik Zabrze.
[3][4] Jonczyk made his debut for the Poland under-15s team on 17 April 2007, scored twice against Slovakia.
[5][6] On 26 March 2009 Jonczyk scored two goals in UEFA European Under-17 Championship elite round match against Slovenia.
[7] On 31 March 2009, he scored two goals in UEFA European Under-17 Championship elite round match against Greece.