Never in mitosis gene A (NIMA)-related kinase 2 (NEK2) is a crucial serine-threonine kinase involved in the process of cell mitosis. However, the precise relationship between NEK2 and esophageal squamous cell carcinoma (ESCC) remains inadequately understood. NEK2 expression in ESCC tissues was assessed through bioinformatics analysis, reverse transcription-quantitative PCR (RT-qPCR) and immunohistochemistry, revealing a correlation with ESCC patient prognosis. Cultured ESCC cells and human normal esophageal epithelial cells (HEEC) were used to investigate the effects of NEK2 knockdown on the development and progression of ESCC by integrated confluence algorithm, colony formation, wound-healing, transwell, and ESCC xenograft tumor model, in vitro and in vivo. In ESCC tissues, NEK2 was found to be significantly upregulated, and its expression correlated with poor prognosis in ESCC patients. NEK2 may facilitate ESCC development by regulating cell proliferation, migration, and invasion. Additionally, results from in vivo experiments suggested that NEK2 knockdown can inhibit tumor growth. Moreover, forkhead box M1 (FOXM1) was identified as a potential downstream target of NEK2 in the regulation of ESCC, with its overexpression reversing the effects of NEK2 knockdown on ESCC. Mechanistic studies also indicated that NEK2 may promote the malignant progression of ESCC by inhibiting cellular senescence through the activation of the FOXM1/c-Myc/p27 signaling pathways, which may provide a novel perspective for the management of ESCC.