At KW, he has curated exhibitions with, among others, Hanne Lippard, Ian Wilson, Adam Pendleton, Ronald Jones, Hiwa K, Willem de Rooij, Beatriz González, David Wojnarowicz, Hreinn Friðfinnsson, and Hassan Sharif.
In 2022, Gruijthuijsen co-curated (along with the former gallerist Kirsten Landwehr) the art installed at the Château Royal hotel in Berlin, including works by John Bock, Thomas Demand and Alicja Kwade.
[2] In 2018, Gruijthuijsen was a member of the selection committee which put forward Moritz Wesseler as director of Fridericianum.
[3] That same year, he served on the jury that selected Sondra Perry for the Nam June Paik Award.
[4] In 2023, Gruijthuijsen served as curatorial advisor of Artissima art fair, alongside Jacopo Crivelli Visconti.