Jeffrey Sinclair is a character in the fictional universe of the science fiction television series Babylon 5, played by actor Michael O'Hare. He was a regular in the first season of the show, as Commander of the Babylon 5 station, and made a number of guest appearances afterwards. Role in Babylon 5 Character arc The character's backstory is given as having been born on Mars Colony. In an early episode of season one, Sinclair states that his family had been pilots "ever since the Battle of Britain" and Sinclair's father was a fighter pilot for EarthForce who participated in the Battle of Balos, the last engagement of the Dilgar Invasion. Sinclair continued the tradition and became a fighter pilot. Sinclair enlisted in EarthForce in 2237. During his time at EarthForce Academy, he met Catherine Sakai, with whom he had a relationship. After a year of living together, the two of them broke up; however, they continued to see each other off and on through 2258, later getting engaged. Sakai went missing in late 2259, while on a mission for the Rangers. The season one episode "By Any Means Necessary" establishes that Sinclair received Jesuit education as a young man. In 2240, Sinclair was promoted to fighter pilot, continuing a Sinclair family tradition that had extended as far back as the Battle of Britain. Less than a year later, Sinclair was promoted to squadron leader; due to his rapid rise through the ranks, the rumor of the day was that Sinclair was on the fast track to making Admiral. As squadron leader, Sinclair fought at the Battle of the Line, the last major battle in the Earth-Minbari War. During the course of the battle, his squadron was destroyed by the Minbari, and his fighter was badly damaged. In a last act of defiance, Sinclair attempted to ram one of the Minbari cruisers. He failed in this when he was captured by another Minbari cruiser for interrogation by the Grey Council. The Council's Triluminary detected Valen's DNA in Sinclair, so they assumed, to their profound shock, that he possessed the soul of Valen, a hero of the Minbari who led them to victory 1,000 years ago against the Shadows. It was concluded by the Grey Council that Minbari souls were being born into human bodies. The discovery of what Sinclair possessed led the Minbari to surrender and return Sinclair to his fighter,