Commander Jeffrey Sinclair is a fictional character from the science fiction television series Babylon 5. He serves as the commanding officer of the space station Babylon 5 during its early years, overseeing diplomatic relations and conflicts among various alien species. Sinclair is portrayed as a strong leader with a deep sense of duty and responsibility. He has a military background and is known for his strategic thinking and ability to navigate complex political situations, often working to maintain peace in a turbulent galaxy.