This study develops and validates a dispositional measure of employability (DME). Dispositional employability was defined as a constellation of individual differences that predispose individuals to (pro)active adaptability specific to work and careers. A dispositional approach to employability represents an alternative conceptualization to those previously found in the literature. Three independent studies were conducted to establish construct validity. Using exploratory factor analysis (Study 1) and confirmatory factor analysis (Study 2), a 25‐item DME instrument was confirmed. Study 2 supported the hypothesized second‐order latent multidimensional factor structure of the DME. Study 3 confirmed the stability of the DME and provided support for its construct validity by longitudinally showing that dispositional employability was significantly related to employees' positive emotions and affective commitment related to organizational changes. It was shown that these effects were above and beyond those found for tolerance for ambiguity, work locus of control, self‐esteem, and optimism. Implications for future organizational research and practice are discussed.