This study examines the influence of career mobility and professional identity on job satisfaction among librarians in Nigerian universities, focusing on the North-East region. A descriptive survey research design was adopted, with a target population of 305 professional librarians in federal and state university libraries. The total enumeration sampling technique was employed, and data were collected using a self-structured questionnaire. Descriptive statistic (frequencies, percentages, mean and standard deviation) and inferential statistic(regression analysis) were used to analyse the data. The findings revealed that career mobility, while recognized as crucial for professional growth, is hindered by insufficient support for advancement, limited professional development opportunities, and lack of clear career pathways. Professional identity was found to be positively related to job satisfaction, with librarians identifying strongly with their role and seeing their work as vital to institutional success. However, pride in being a librarian was generally low, and librarians expressed dissatisfaction with their work environment, particularly concerning salary, promotion opportunities, and job security. Statistical tests confirmed significant relationships between career mobility and job satisfaction (r = 0.427, p < 0.05), and professional identity and job satisfaction (r = 0.391, p < 0.05). The study recommends that Nigerian universities should strengthen career development through regular training, fair promotions, and mentorship while enhancing librarians' professional identity by recognizing their contributions, encouraging collaboration, and supporting the adoption of new technologies.