Under his artistic and executive directorship, KW and the Berlin Biennale were started as self-inventive initiatives and are now federally and state funded institutions.

[9] Biesenbach joined MoMA PS1 as a curator in 1996; the museum's director Alanna Heiss had hired him part-time while allowing him to maintain his directorship in Berlin.

He drafted an open letter to the then New York City Mayor, Michael R. Bloomberg and fellow New Yorkers that called for help in the Rockaways, where he had purchased a house in early 2012,[12] signed by celebrities including Lady Gaga, Madonna, James Franco, Gwyneth Paltrow and Patti Smith.

[10] During his time as director, Biesenbach introduced free admission to the museum with a $10 million gift from Carolyn Clark Powers,[14][15] founded the first Environmental Council at any American museum[16] and started the Performance Space Wonmi's Warehouse Programs[17] while commissioning Larry Bell's, Bill and Coo and Untitled by Barbara Kruger as public art projects.

[20] In addition, he fundraised with artists' designed facemasks[21] by Yoko Ono, Catherine Opie, Pipilotti Rist, Mark Grotjahn, Barbara Kruger, Hank Willis Thomas, Virgil Abloh, Alex Israel and sold them internationally in collaboration with the Warhol Foundation, the Qatar Museums and the K11 Hongkong.

[23][24][25] Klaus Biesenbach is a prominent figure in climate activism within the art world, particularly through his work at major institutions like MOCA in Los Angeles and the Neue Nationalgalerie in Berlin.

[27] His approach underscores the vital role museums play in addressing pressing global challenges, including the climate crisis, by fostering spaces for public engagement and protest.

His homes, whether in Los Angeles or New York,[31] are curated with a stark simplicity, emphasizing functionality[32] and the presence of art over material accumulation.