Born to Jorel and Lara in the science capital on Vathlo Island on Krypton, baby Kalel was sent to Earth to escape his homeworld's destruction. He was found and raised by a human couple. As an adult, he operates as Superman while also serving as the President of the United States on Earth-23.
Calvin Ellis made his debut in Final Crisis #7, being that his only appearance before the Flashpoint reboot. Beyond being revealed that Nubia and him were from the same Earth and his job, little was known about him. According to creator Grant Morrison Calvin is based on former president Barrack Obama and boxer Muhammad Ali.
Major Story Arcs
During the Final Crisis, Calvin was recruited by Renee Montoya to join the Supermen of the Multiverse to help battle the dark monitor Dax Novu.
The Curse of Superman
One day, inhabitants from an alternate Earth (scientists Clark Kent, James Olsen and Lois Lane) came through a transmatter symphonic array to his Earth, running away from Superdoom, their universe's Superman who already had killed other Superman variants. When the evil Superman came through, Superman fought him and won, with the help of his archenemy, Lex Luthor.
In Multiversity, it was revealed that Superman (Calvin Ellis) is a member of his own world's Justice League composed mostly of Afro-American heroes. When Thunderer sent out a multiversal SOS throughout the 52 universes, Calvin was the last summoned. However, he was ready to help rescue the last Monitor and stop the menace of the Gentry, despite the resistance of the Retaliators of earth-8.
In time, President Superman would discover that Nix Uotan had been corrupted by the Gentry and was attacking earth-8. With the help of the heroes of several parallel earths, the menace of the Gentry was stopped, but not before discovering the source of all their recent problems: earth-33.
Worried about the potential threats than could menace the multiverse, President Superman asked for volunteers to form a multiversal task force to defend all the universes in the event of another attack: Operation Justice Incarnate was born. For President Superman, it's just another job on top of his Presidency and work as Superman.
The story is centered around the Earth 0's Superman, however, Calvin still plays a prominent role in this arc. A threat is approaching the main earth. Calvin, needing backup, travels to other earths to form a team of "Supermen". Eventually, it is learned that the threat's only goal is the extinction of all Supermen throughout the multiverse. Fortunately, the Superman are able to work together to eliminate this threat.
When Earth 23 is attacked by a manifestation of the Dark Multiverse, Superman is one of its victims. In his time of need, a lost Wally West comes to President Superman's rescue. Earth 23's Justice League of America attacked Wally, thinking him to be behind the disturbance, but Calvin stops them. Wally explains that he was attacked by creatures who were byproducts of a tear between universes where the dark matter was bleeding into the earth and that in one hour, the planet will be devoured. To stop the dark matter's expansion, Calvin elected to use the anti-life bomb, a weapon that would kill millions of people, as a last resort. Wally West then intervened, racing to the center of the tear, only to find the Retaliators and the Zen-Men, heroes from earth 8, who had a similar issue on their own earth. After Wally stopped the menace, Calvin stopped the anti-life bomb and gave the troubled flash words of comfort. President Superman offered his help, but Wally, instead, chose to leave on his own in search of the next dark matter event.
DC's Very Merry Multiverse
President Superman appeared again in DC's Very Merry Multiverse. Here, Ellis is celebrating a global Earth 23 holiday known as the Celebration of Rapport. This holiday includes people placing a self-stone, an orb that holds an individual's hopes, fears, joys, and sorrows, into a giant container. From there, you give away your self-stone and receive a knew one to replace it. The first day is known as the Day of Giving, while the second day is the Day of Receiving.
While the world enjoyed the Celebration of Rapport, Earth 23 Bizarro felt differently, as he had never received a self-stone during the Celebration of Rapport. After meeting up with the Earth 23 versions of Darla and Kilowog, each grabbed one of the filled-up giant containers, intending to transport them in preparation for the Day of Receiving. It was then that Bizarro attacked. Bizarro and President Superman fought ferociously until one of Superman's strikes had Bizarro hurtling towards the ground. Bizarro found himself on top of a pile of self-stones. Bizarro was still enraged, but his anger subsided when a little girl approached him and gave him her self-stone, thus ending the conflict.
Infinite Frontier: Secret Files
President Superman, along with a cadre of presidential advisors, is in the oval office discussing an approaching alien armada. His advisors want to bring in Superman, but Ellis suggests that they try to find a way to defeat the armada without Superman's intervention. After President Ellis dismisses his advisors, he talks with Kelex and his assistant, Courtney about how limited his time is but also ensuring them that though he doesn't want America to overly rely on him, he, as Superman, would always be there to save the day.
From there, President Superman flew around, battling different threats. As he fought a giant robot, he remembered how he used to have an army of robotic Ellis's used to conceal his identity until they were compromised by the Brainiac Operating System. After defeating the giant robot, President Superman met with Machinehead to brainstorm ways on how they could literally create more time. This was followed by a visit with his parents and then a meeting with the Markovian ambassador.
After more diplomatic ventures were over, President Superman found himself fighting a radioactive villain known as the Kryptonite Man, a being that gives off a Kryptonite-like energy; after leaving a coming back with a containment suit, President Superman would defeat him as well. President Superman's day was far from over. After sighting a multiversal breach, President Superman flew into it and after about an hour, came back injured but victorious, having bested the threat on the other side.
President Superman finds time to find a little girl's lost dog before returning to the White House. There, his advisors tell him of a way that they could potentially end the armada threat sans Superman. After this, President Ellis takes a bit of time to himself, using a special key he got from the Black Martians to enter an extra dimensional space so that he may destress. After four minutes in this space, President Superman emerges, renewed. Ellis concludes his day by taking down the armada himself.
After crash landing on Earth 23 in a space ship composed of an unknown material, Flashpoint Batman (Thomas Wayne) is taken to the Justice Incarnate base, the House of Heroes. After awaking, thinking he is under attack, this Batman attacks Machinehead and Captain Carrot. The team is joined by President Superman who explains to Flashpoint Batman who they are and where he is. After Ellis enquires about who injured him, Wayne, frustrated, tells him to just ask Barry Allen.