|“||Hell, I'll probably still be here when they turn off the lights.||„|
|~ Zack predicting he'd be on the station until the end.|
|“||What you're going to have is my foot 16 inches up your butt unless you get the hell out of my way!||„|
|~ Zack, to an uncooperative ISN reporter.|
Zack Allen was a supporting hero on the 1990s science fiction TV series Babylon 5.
A member of Earth Force, Zack transferred to Babylon 5 in late 2258, just before station Commander Jeffrey Sinclair was recalled to Earth. Before coming to Babylon 5 Zack had something of a troubled past, but Michael Garibaldi still insisted on hiring him for security.
After Garibaldi recovered from being shot in the back by his former second in command Jack, Zack quickly became good friends with Garibaldi, and became his second in command.
In 2259 Zack joined Nightwatch, thinking it was an easy extra 50 credits a week on top of his regular pay. Over the next year he began to see the true fascist nature of the organization, and was deeply disturbed to see Nightwatch acting against people who spoke out against President Morgan Clark.
Becoming more uneasy over what Nightwatch was doing, he decided to turn against them in the wake of Clark's declaration of martial law. He worked with John Sheridan and the senior staff to entrap Nightwatch, disarm, and place them under arrest. Zack continued working security under Garibaldi afterwards, working with the Narn who had replaced the Nightwatch officers.
When Clark began bombing civilian targets on Mars, Sheridan responded by declaring Babylon 5's independence from the Earth Alliance. Zack fought alongside Michael Garibaldi and station security against EA Marines who boarded the station. After the security forces managed to subdue the Marines and arrest those who survived, Zack helped a wounded Garibaldi find a safe spot to rest while Zack attended to matters.
Zack became friends with Lyta Alexander and developed feelings for her, but never acted on his feelings for her.
After a brainwashed Michael Garibaldi resigned the following year, Zack Allen became the head of security on Babylon 5. He would remain on the station as head of security for several more years, first under the command of Sheridan, then under the command of Elizabeth Lochley.
Zack suffered an injury some time after 2263 that limited the amount of use Zack had of his right leg.
Some time after 2263 Zack left EarthForce for a time. He initially went back to Earth, but he later returned to Babylon 5 in 2280 and resumed his old job as head of security while the station was being prepared for shut down and scuttling. Because of this the Anla'Shok were unable to find him on Earth for Sheridan's final dinner. Before his passing beyond the rim, Sheridan came to see Babylon 5 one last time, and met Zack for the last time. The prediction Zack made to Sheridan many years earlier that he would still be on B5 when they turned out the station's lights would become true after Sheridan's passing as he would be there for the decommissioning ceremony. The station was shut down, and the station self destructed a few minutes later.