Following a failed first marriage in his college years to Elizabeth Lochley (Learning Curve, Strange Relations), he later married his sister Elizabeth's long-time friend, Anna (Revelations), who was killed on a mission to the galactic rim in 2256 (In the Shadow of Z'ha'dum, the novel The Shadow Within).

Commander John Sheridan was the only Earthforce member to successfully destroy a Minbari war cruiser, the Black Star, during the Earth-Minbari War (In the Beginning) and was awarded a medal of valour for it (And Now For a Word, The Illusion of Truth) - although the Minbari themselves refer to him as "Star Killer" (Points of Departure).

He was promoted to Captain of the Agamemnon, the first Omega class destroyer out of the construction yards after the War (And Now For a Word).  He was assigned command of Babylon 5 because the new administration of President Clark thought he would be more sympathetic to their policies than Commander Sinclair (Points of Departure).

Subsequently he developed a relationship with Ambassador Delenn (A Race Through Dark Places, Confessions and Lamentations, Shadow Dancing), has been captured by the alien Strieb (All Alone in the Night), provided limited assistance for the trouble-stricken Narn (Acts of Sacrifice), and received personal training from Kosh preparing him "to fight legends" (Hunter, Prey, There All the Honor Lies).

He is finally told of his wife's fate and of the re-emergence of the Shadows by Kosh and Delenn (In the Shadow of Z'ha'dum) before being given joint command with Delenn of the Rangers on Babylon 5 (The Long, Twilight Struggle).  After the Vorlons were satisfied that he was the right person for the job (Comes the Inquisitor), he began the campaign against the Shadows as well as EarthGov itself following President Clark's illegal orders to maintain control (Messages From Earth, Point of No Return, Severed Dreams).

When his wife apparently returned to him (Shadow Dancing) he accompanied her back to Z'ha'dum where he was prepared to sacrifice his life to stop the Shadows (Z'ha'dum).  However, with the aid of the alien Lorien, he survived the experience (albeit with only another 20 years to live (Falling Toward Apotheosis)) to return and propose to Delenn (Falling Toward Apotheosis), and end the Shadow War (Into the Fire) before launching his final campaign against Clark (No Surrender, No Retreat).

When Garibaldi betrayed him he was captured by Earthforce agents (The Face of the Enemy), and interrogated and tortured in an attempt to make him confess his conspiracy with alien governments to undermine President Clark's authority (Intersections in Real Time).  After his rescue, he took command of the Agamemnon for the final assault against Earth (Between the Darkness and the Light, Endgame).

When the new Interstellar Alliance was formed, he was appointed President and married Delenn (Rising Star).  He and Delenn eventually have a son, David (War Without End, Part II, Wheel of Fire, the novel Out of the Darkness).  He declines re-election as President of the Alliance sometime in 2279, passing the task to Delenn.  At the end of his life, he makes a final visit to Babylon 5 and finally passes beyond the Galactic Rim to begin a new journey of life (Sleeping in Light).

Played by Bruce Boxleitner, who appeared in the movie Tron, among others, and also the TV series Scarecrow and Mrs King.  He is also the author of two science-fiction novels, Frontier Earth and Frontier Earth: Searcher.