John J. Sheridan is the lead character in the fictional universe of the science-fiction television series Babylon 5, played by Bruce Boxleitner.

John Sheridan is portrayed as an incorruptible, dynamic, idealistic, and charismatic leader who can inspire fierce loyalty in his subordinates.

However, Sheridan is shown at times to be reckless and stubborn, and like his second-in-command Susan Ivanova he possesses a fierce temper that can lead to occasional explosive outbursts of anger.

His second wife, Anna Sheridan, was (apparently) killed while exploring a distant planet, and when he takes command of Babylon 5 at the start of Season 2 her death still troubles him.

Kosh, not wanting to reveal his true form, appears as a different religious figure depending on the onlookers' home world.

As a young man he joined Earthforce, was married briefly to Elizabeth Lochley, and by 2245 had risen to the rank of lieutenant commander.

The Prometheus later was the ship that precipitated the Earth-Minbari War when it fired on a Minbari warcruiser during Earth's disastrous first contact with that race.

With the Lexington crippled and unable to fight, Sheridan mined several nearby asteroids with nuclear weapons and lured the Black Star back towards his ship with a distress signal.

Soon after his arrival, in "Points of Departure," the Minbari ship Trigati, which had disappeared during the Battle of the Line, reappeared and tried to provoke him into firing upon it.

A group of Centauri civilians attempted to assassinate Sheridan, but he was saved by Vorlon Ambassador Kosh, and the formality of the apology was dismissed in view of this event.

On his first mission in command of White Star One, he helped Rangers stationed at a training camp under Centauri blockade escape before being captured by the Shadows.

Sheridan realizing that his position was hopeless was prepared to accept defeat, but at that moment Delenn came to his rescue, leading several Minbari War Cruisers to the station, while herself commanding White Star One.

Sheridan, Delenn, Marcus Cole, Ambassador Sinclair, Lennier, and Ivanova went back in time to intercept Shadow allies who were on their way to destroy that station.

Sheridan married three women, and while only one was Minbari, each represented a different caste: Anna (Worker), Elizabeth (Warrior) and Delenn (Religious).

Meanwhile, Sheridan, about to be killed by the explosion, jumped off the balcony into a pit that was miles deep after hearing the voice of Ambassador Kosh instructing him to do so.

With Delenn, he led the alliance of Humans, Narns, Minbari, and the League of Non-Aligned Worlds, known as the Army of Light, against the Shadows.

In "Into the Fire," at the Battle of Coriana VI, Lorien confronted the Shadows and Vorlons telling them they must depart with the last of the First Ones "beyond the rim" of the galaxy.

Sheridan has made use of nuclear devices on at least four separate occasions: against the Minbari flagship, the Black Star; at Z'ha'dum; at Coriana 6; and again during the events of Thirdspace.

While touring the Agamemnon, Sheridan received a message from Michael Garibaldi that his father had been captured by Clark's forces, and asked him to come to Mars.

Susan Ivanova was mortally wounded when her command ship, the White Star 2, collided with debris from one of the destroyed enemy vessels in "Between The Darkness And The Light".

In the episode "Endgame," Sheridan was able to use telepaths to disable most of the loyalist Earthforce Alliance ships, stationed at Mars, saving many thousands of lives on both sides.

Delenn announced that the members of the League of Non-Aligned Worlds had voted to dissolve that body, and enter into a new Interstellar Alliance.

After his inauguration, Sheridan gave shelter to a group of refugee telepaths led by a man named Byron, and allowed them to form a colony on Babylon 5.

In addition to helping save Sheridan's life, Byron himself learned that the Drazi - who were members of the Alliance - were using raiders to harass the Enphili.

In Babylon 5: A Call to Arms, five years after the founding of the Alliance, Sheridan would overlook the construction of the Victory-class ship, which was a Destroyer Class White Star.

While he was overseeing the ship's development, Galen, a technomage contacted John and warning him that the Drahk were returning to exact revenge against the Alliance in a big show of force by wiping out Earth's population with a Shadow Planet Killer which was the last type of its weapon known to exist in the galaxy after their masters, The Shadows left beyond the rim.

In a dream, the technomage Galen warned him that in thirty years Vintari would launch a terrible military campaign to destroy Earth, and only his death at Sheridan's hands could stop him for sure.

Sheridan chose a different path, allowing Vintari to fly in a Starfury beside him as he had always dreamed, and inviting him to stay in the Alliance's headquarters, safe from assassination attempts which were becoming increasingly common in the Centauri royal court.

In this way, he hoped to show Vintari the concept of kindness for its own sake, rather than the quid pro quo nature of assistance common on Centauri Prime.

Sheridan learned that Allan had re-enlisted a few months prior and returned to Babylon 5, which resulted in the Ranger carrying his invitation being unable to find him on Earth.