Updated project metadata. The role of Rad53 in response to a DNA lesion is central for the accurate orchestration of the DNA damage response. Rad53 activation relies on its phosphorylation by the Mec1 kinase and its own autophosphorylation in a manner dependent on the adaptor Rad9. While the mechanism behind Rad53 phosphorylation and activation has been well documented, less is known about the processes that counteract its kinase activity during the response to a DNA break. Here, we describe that PP4 dephosphorylates Rad53 during the repair of a DNA lesion, a process that affects the phosphorylation status of multiple factors involved in the DNA damage response. PP4-dependent Rad53 dephosphorylation stimulates DNA end resection in a process that relies mainly on Sgs1/Dna2. Consequently, elimination of PP4 activity affects DNA resection and repair by single-strand annealing, defects that are bypassed by reducing the hyper-phosphorylation state of Rad53 observed in the absence of the phosphatase. These results confirms that Rad53 is one of the principal targets of PP4 during the repair of a DNA lesion and demonstrate that the attenuation of its kinase activity during the initial steps of the repair process is essential to efficiently enhance recombinational repair pathways that depend on long-range resection for its execution.