Does Steve Rogers AKA Captain America actually hold the rank of Captain in the U.S. Army? Portrayed by Chris Evans, Captain America is one of the most beloved superheroes in the Marvel Cinematic Universe. Steve Rogers debuted in 2011's Captain America: The First Avenger and starred in two sequels, 2014's Captain America: The Winter Soldier and 2016's Captain America: Civil War, as well as all four Avengers films. Evans also cameoed in Thor: The Dark World, Spider-Man: Homecoming, Captain Marvel, and a clip of him appeared in Agent Carter.
Steve Rogers has one of the most endearing origin stories in the MCU: In the midst of World War II, Rogers was continually rejected by the U.S. Army because of his diminutive size and health issues. However, Steve's determination caught the eye of Dr. Abraham Erskine (Stanley Tucci), who saw qualities in Rogers that made him an ideal candidate to become propaganda films.
It's easy for fans to miss this detail in Captain America: The First Avenger but Steve Rogers really was promoted to the rank of Captain during the course of the film. After Erskine was killed and Steve tried to avenge him by chasing after the Hydra agent, Senator Brandt (Michael Brandon) hired Private Rogers for the USO Tour and he "promoted" Steve on the spot. However, that "promotion" was likely tongue-in-cheek since Brandt wanted Rogers to be "Captain America" on stage. It wasn't actually until Steve went to Europe, initially to entertain the troops with his act (which the soldiers soundly rejected), that Private Rogers eventually earned his promotion to Captain and he truly became the superhero he portrayed in his Captain America movies and on his USO tour.
When Steve went on the mission to rescue Bucky Barnes (Sebastian Stan) and 400 POWs from a Hydra base, he was airlifted by Howard Stark (Dominic Cooper) and he joked to Peggy that he can give her orders because "after all, I am a Captain" before he leaped out of the plane. But it was the fact that Rogers successfully brought Bucky and the POWs (some of whom would go on to become his team called the Howling Commandos) back to Col. Phillips' army camp that earned him an extraordinary battlefield promotion.
Senator Brandt wanted to award Steve with the Medal of Honor for his heroism in Europe, but Rogers no-showed the event back in the States. Instead, Steve went to London - but as Captain Steve Rogers (rank O-3), as evident by the captain's stripes on the shoulders of his uniform when he recruited the Howling Commandos and raised Peggy's ire after she caught Steve kissing Private Lorraine (Vibranium shield.
Leaping forward multiple ranks from Private E-1 to Captain O-3 is certainly uncommon, but then again, Steve Rogers was no common soldier. After being frozen in ice for 70 years and reawakened in 2012, Rogers permanently retained his rank and he was properly referred to as Captain Rogers when he was an Agent of SHIELD and the leader of the Avengers. And even after Steve gave up the shield and title of Captain America, when he went rogue after violating the Sokovia Accords and again after Avengers: Endgame, he remains Captain Steve Rogers then, now, and forever.