Drought is a primary factor constraining the growth and development of Kentucky bluegrass (Poa pratensis L.). To elucidate the molecular mechanisms underlying drought and saline-alkali stress responses, the cultivar 'K.B.G' was used as the experimental material. An R2R3-MYB transcription factor gene, PpMYB4, and its promoter were cloned and functionally characterized. Subcellular localization analysis, confirmed by DAPI co-staining, demonstrated that PpMYB4 is targeted to the nucleus, consistent with its role as a transcription factor. Phylogenetic analysis revealed the closest relationships with MYB4 homologs from Brachypodium distachyon, Lolium rigidum, and wheat (Triticum aestivum). RT-qPCR showed that PpMYB4 is preferentially expressed in stems and is transcriptionally responsive to drought, saline-alkali stress, and multiple phytohormones (SA, IAA, MeJA induced; ABA, GA repressed). Overexpression of PpMYB4 in Kentucky bluegrass, confirmed by PCR-based transgene detection and qRT-PCR, promoted vegetative growth, enhanced rooting, and increased epicuticular wax deposition on leaf surfaces. Under drought stress, overexpression lines maintained higher relative water content, lower electrolyte leakage, and elevated SOD and POD activities compared with wild-type plants. Promoter deletion analysis identified an upstream region critical for transcriptional activity and demonstrated drought-inducible promoter function. These findings establish PpMYB4 as a multifunctional regulator of wax accumulation and antioxidant defense in Kentucky bluegrass, providing a candidate gene for molecular breeding of drought-resilient turfgrass.