We demonstrate that the mitogen‐activated protein kinases extracellular signal‐regulated kinase (ERK)‐1 and ERK‐2 have a central role in mediating T‐cell receptor‐dependent induction of IL4 expression in human CD4⁺ T cells. Significantly, this involved a novel mechanism wherein receptor cross‐linking induced activated ERK to physically associate with a promoter element on the IL4 gene. The proximally localized ERK then facilitated recruitment of the key transcription factors necessary for initiating IL4 gene transcription. Although both ERK‐1 and ERK‐2 bound to the promoter, recruitment of either one alone was found to be sufficient. We thus identify a novel mode of function for ERK wherein its physical association with the promoter serves as a prerequisite for enhanceosome assembly. This unusual pathway is also indispensable for human Th2‐cell differentiation.