Career development is described as the interactive progression of internal career identity formation and the growth of external career significance. Argued is the need for a content model of career development where the field is dominated by process theories. A theory is put forward of career development crystallizing in the acquisition of career roles. The new concept of career roles is outlined as a descriptive tool for careers, and a model of 6 universal career roles is presented. Not jobs but career roles are proposed as units to describe careers. A first study on self- and peer-reported career roles in relation to career success and career satisfaction is reported. Career roles were measured and distinguished reliably. Results indicate that combining different career roles predicts success as well as satisfaction. Research perspectives with the career roles construct are discussed. (Contains 7 tables and 1 figure.)