- "Here's the truth, a reporter got greedy for a scoop and went where she shouldn't have. Superman acted like some rogue combatant to rescue her, and people died. Don't invent a conspiracy theory to put back his halo. Or yours."
- — Calvin Swanwick to Lois Lane
Lieutenant General Calvin Swanwick is a high-ranking General of the U.S. Armed Forces and former Combatant Commander for United States Northern Command, who currently serves as the U.S. Secretary of Defense.
General Swanwick was alerted to the mission control room at Peterson Air Force Base when a huge UFO settled into orbit near Earth. Shortly thereafter, a menacing message was sent all across the Earth from the extraterrestrial General Zod, who demanded that a fellow alien from his planet, a man named Kal-El (who had tried to blend in with Earth's population for decades), be handed into his custody, and that if the latter wasn't turned in to Zod within 24 hours, the entire planet would suffer severe consequences of apocalyptic proportions.
Kal-El himself arrived at a military base shortly afterwards, surrendering if Lois Lane was to be freed. Kal-El and Lois sat in an interrogation room where the General questioned Kal-El on his motives, before handing him over to Zod's second-in-command, Faora Hu-Ul, who requested that Lois come too.
After the Battle of Smallville, Kal-El (now nicknamed "Superman") and Lois came, along with Kal-El's Spaceship, telling the General how to send Zod and his followers back to the Phantom Zone, this time permanently. The plan was to collide the Phantom Drive of Superman's infant starcraft with Black Zero's, in an attempt to create an unstable Phantom energy singularity, which would suck all of Zod's forces back into the Zone. Before they could do so, however, Superman would have to personally destroy Zod's World Engine and end Earth's terraformation. Swanwick agreed to the plan and ordered the attack, after which Superman promptly took flight to the Indian Ocean.
Ultimately, while the plan was successfully executed (with only Zod remaining on Earth), it came at the cost of Colonel Hardy and Dr. Hamilton's lives, with only Lois escaping the singularity's pull, due to Superman's timely intervention. Nonetheless, Earth and all of humanity had been saved from the alien invasion.
Age of Superman
Shortly after the end of the Kryptonian invasion, General Swanwick had drones try to track down Superman's whereabouts, determined to find his address. Superman, however, wasn't pleased, and proceeded to slam one of the drones into the ground, right in front of Swanwick's car, much to the latter's dismay. Superman assured the general that, having grown up in Kansas, he was technically an American himself, so he would never act against the United States' interests. However, while Superman would always remain an ally to both America and all of Earth, he requested that it be done on his own terms, and that he trusted Swanwick's ability to convince Washington D.C. of that. With that said, Superman took flight again at supersonic speeds, leaving Major Farris smiling, self-admittedly in awe of the handsome alien.
Secretary of Defense
In the aftermath of a Superman's appearance, Swanwick was appointed as the United States Secretary of Defense. He was ambushed in the male toilets by Lois Lane, who was investigating prototype military grade ammunition that was used in the Superman incident in Nairomi. He was upset over the incident, stating she went to Nairomi for a scoop out of greed and Superman showing up to rescue her being was responsible for the death of people there.
Swanwick dismisses Lois away but takes the bullet she gives him. He later meets with her in civilian diguise on the banks of Potomac River, who discloses that LexCorp Industries are the supplier of bullets, and that Lex Luthor had militia in Nairomi led by Anatoli Knyazev to pick up Kryptonite but it went sour.
As Doomsday emerged from the Scout Ship, Superman engaged the monster and tried to take him away from Metropolis and throw him off the Earth. Swanwick received a phone call from the President to fire a nuclear warhead at the 2 Kryptonians. Swanwick tried to dissuade him as it would kill Superman as well. To his regret, the President reluctantly persisted and they fired the nuke, with Doomsday landing on Stryker's Island while the signal to Superman was lost.
- Swanwick's first name was never revealed until Batman v Superman: Dawn of Justice, in which we learn that his first name is Calvin.