Aging, cancer, and longevity have been linked to intracellular Ca2+ signaling and nociceptive transient receptor potential (TRP) channels. We found that TRP canonical 7 (TRPC7) is a nociceptive mechanoreceptor and that TRPC7 channels specifically mediate the initiation of ultraviolet B (UVB)‐induced skin aging and tumor development due to p53 gene family mutations. Within 30 min after UVB irradiation, TRPC7 mediated UVB‐induced Ca2+ influx and the subsequent production of reactive oxygen species in skin cells. Notably, this function was unique to TRPC7 and was not observed for other TRP channels. In TRPC7 knockout mice, we did not observe the significant UVB‐associated pathology seen in wild‐type mice, including epidermal thickening, abnormal keratinocyte differentiation, and DNA damage response activation. TRPC7 knockout mice also had significantly fewer UVB‐induced cancerous tumors than did wild‐type mice, and UVB‐induced p53 gene family mutations were prevented in TRPC7 knockout mice. These results indicate that TRPC7 activity is pivotal in the initiation of UVB‐induced skin aging and tumorigenesis and that the reduction in TRPC7 activity suppresses the UVB‐induced aging process and tumor development. Our findings support that TRPC7 is a potential tumor initiator gene and that it causes cell aging and genomic instability, followed by a change in the activity of proto‐oncogenes and tumor suppressor genes to promote tumorigenesis. Schematic representation of the role of TRPC7 as a potential tumor initiator gene in ultraviolet B (UVB)‐induced aging and cancer progression. UVB‐activated TRPC7 initiates skin aging via intracellular Ca2+ elevation, resulting in oxidative stress, DNA damage response activation, abnormal differentiation, and senescence inflammation response activation; this pathology is repaired with the activation of p53 to maintain tissue homeostasis. When homeostasis is no longer maintained and the aging process is activated, carcinogens promote cancer progression. TRPC7 initiates tumorigenesis by causing genomic instability, thereby changing the activity of proto‐oncogenes and tumor suppressor genes.