In July 2012, Fornalik became the coach of the Poland national football team after the dismissal of Franciszek Smuda.

[7] Under Fornalik's rule, Piast turned into overachievers, consistently competing for spots in the upper half of the table, which resulted in winning the championship at the end of the 2018–19 season, finishing third two years later and two short-lived European campaigns.

On 25 October 2022, following a poor start to the 2022–23 campaign, Fornalik left Piast and was replaced by Aleksandar Vuković two days later.

[8] On 29 November 2022, Fornalik was announced as the new head coach of Zagłębie Lubin, agreeing to a contract until the end of the 2023–24 season.

[10] On 22 September 2024, Zagłębie suffered a 1–5 away loss to Raków Częstochowa, leaving the club in relegation zone with eight points after nine rounds of the 2024–25 season.