Although condensin protein complexes have long been known for their central role during the formation of mitotic chromosomes, new evidence suggests they also act as global regulators of genome topology during all phases of the cell cycle. By controlling intra-chromosomal and inter-chromosomal DNA interactions, condensins function in various contexts of chromosome biology, from the regulation of transcription to the unpairing of homologous chromosomes. This review highlights recent advances in understanding how these global functions might be intimately linked to the molecular architecture of condensins and their extraordinary mode of binding to DNA.