|A character from Stargate SG-1|
|Planet of origin||Earth|
Stargate Command embarkation room
|Allegiance||Air Force Special Operations|
|Out of Stargate universe information|
|Portrayed by||Marshall Teague|
|First appearance||"A Matter of Time"|
Frank Cromwell and Jack O'Neill used to be friends. But when O'Neill, who was in the Special Forces, he has been hit and left behind by Crowmell who made a decision to save the rest of the team. Even if he wanted to go back and rescue O'Neill, he didn't, thinking that O'Neill was dead. O'Neill has been taken prisoner in an Iraqi prison for four months. Because of this, O'Neill took Cromwell for responsible to have been abandoned behind enemy lines (SG1: "A Matter of Time").
As all communications have been lost with Stargate Command, Colonel Cromwell and a Special Forces unit are sent in the facility right to sub-level 28. They meet Dr. Janet Fraiser who tells them that, unlike what they thought, SGC is not under alien invasion.
When Colonel Jack O'Neill eventually meets Cromwell, he is surprised to see him sent by the Pentagon. O'Neill introduces Cromwell to Captain Carter. Carter realizes that time is really slowing down because of the black hole thanks to Cromwell's watch. General Hammond meets Cromwell as well. Hammond orders the complete evacuation of the facility but asks for two volunteers to remain and set the auto-destruct sequence. O'Neill and Cromwell volunteer.
Alone in the SGC control room. Crowmell discovers the image of Henry Boyd, visibly scared. Some time later, O'Neill asks Cromwell to enter an identification code on the computer to initiate the self-destruct sequence. But when Cromwell reminds O'Neill his misadventure in Iraq, O'Neill is quite upset with this.
Carter eventually comes in with a new idea, sending a shaped charge through the wormhole in order to provoke a power surge big enough to force the Earth Stargate to jump to another gate (SG1: "Solitudes"). Cromwell and O'Neill agree to do it. When a chair shatters the control room windows, some shards of glass wound Cromwell. O'Neill eventually orders Cromwell to set the timer to 20 seconds. But as the bomb timer is set, the iris is ripped, bent then sucked right into the wormhole. O'Neill is sucked in as well but Cromwell manages to grasp him. O'Neill orders Cromwell to start the countdown, but a shard of glass cuts Cromwell's rope. O'Neill grasps him but Cromwell eventually releases O'Neill's hand, sacrificing himself. He is sucked into the distorted wormhole like the iris before him.
- Cromwell's nationality is deducted as he's part of the Air Force Special Operations.
- Cromwell's instant death in the wormhole is obvious as he has been sucked into it the same way as the iris. The iris is made of pure titanium, a metal that has a high strength, yet it was shaken, torn apart and directly ripped out from the Stargate. Then it has been sucked into the distorted wormhole quickly. The gravitational attraction of the black hole is quite huge.
Cromwell sacrifices himself to allow Col Jack O'Neill to start the bomb's countdown.