In today's world, the surrounding environment and organizations are constantly requiring individuals to engage in lifelong learning and develop boundaryless careers. In this paper, the antecedents of career movement for librarians or those working in related organizations will be identified and conceptualized. To this end, this study establishes a theoretical model of internal and external career movement and its antecedents, verifies a model based on surveying librarians working at libraries and those whose functions are similar to those of librarians, and conducts usefulness analysis while exploring a new model. In the previous study, a structural equation model, originally designed for careers other than librarians, was applied to the targets of this study, librarians, to assess external validity. This study, however, sets out a new model because the basic model cannot fully explain the structure of the data. The new model has good fit and also offers a good explanation of a covariance matrix of the original data. The significance of all coefficients, except for the covariance between career development support and external career movement intention, are statistically significant. (Contains 3 figures, 7 tables, and 1 note.)