The Local Government Engineering Department (LGED) is renowned for its superior effectiveness compared with other public organizations in Bangladesh. Using the management and organizational theory framework, this paper attempts to answer the following two related questions: (i) why is LGED so effective, and (ii) has there been complementarity between LGED's own strengths and the capacity development support of its donors. LGED's business domain has been conducive to its effectiveness and to the mobilization of resources which it has used tactically to improve its effectiveness. LGED's main strengths have been in the organizational behavior elements, which were formed over time by the leadership and practices of the founding chief executive and his close associates, but LGED has also created a certain effective level of organizational structure. While weaknesses have persisted in procedures/rules of financial management, audit, quality assurance, etc, they have been balanced by the strengths in organizational behavior and structure, and further strengthened since the 1980s through capacity development support from donors. LGED is an interesting case because it has been successful without having fully adopted key recommendations of New Public Management on organizational management, such as transformation to agency, merit-based personnel management, and decompression of salary structure. In the final section of this paper, policy implications are presented for improving the performances of other public organizations in Bangladesh and for enhancing the performance of LGED.