Kruk was a member of the executive between June 1928 and October 1930, sharing the seat with the Yugoslav socialist leader Živko Topalović (like Drobner had done as well).
He shared his seat with the Bulgarian socialist leader Yanko Sakazov until August 1925, then sharing it with Bolesław Drobner of the Independent Socialist Labour Party of Poland until June 1928 and from June 1928 to January 1929 with Joseph Kruk.
As of the late 1950s and early 1960s, the executive committee of SUCEE consisted of Zygmunt Zaremba (chairman), Brūno Kalniņš (vice chairman), Živko Topalović (vice chairman), Vilém Bernard (secretary) and Imre Szelig (treasurer).