This study examined the influence of career choice on professional and job commitment, factors influencing career choice, the perceptions on professionalization and the extent to which career choice has influenced the growth, job and professional commitment of librarians in selected libraries in Oyo and Ogun states of Nigeria. Descriptive survey research design was adopted with questionnaire as the research instrument. The reliability co-efficient of the instrument was 0.83. The statistical methods used to analyze the data obtained were descriptive statistics of frequency distribution counts, percentages and tables for the demographic variables and standard deviation for research questions. Findings revealed that intellectual development obtained the highest score (61.8%; mean 4.26, Std Dev. = 1.17), as the greatest factor that influences career choice of librarians, while findings also showed that the major perceptions of librarians about the professionalization of librarianship was poor as majority of the respondents indicates they hate being librarians though majority indicated that their career choice of librarianship has influenced its growth (scores = 118; 69.8%; mean 4.72; StdDev = .50). The study concludes that intellectual development played significant role in the career choice of librarians. The study recommended that intellectual development activities should further be intensified in librarianship.