A male human known as Drawd Munbrin, who served the Galactic Empire, held the military rank of chief and naval captain. He was an [imperial_recruitment_officer] tasked with finding new recruits. In 13 BBY, Munbrin was stationed at Coronet Spaceport when he first met Han, who would later become a well-known smuggler. It was Munbrin who bestowed the surname Solo upon Han.
Drawd Munbrin, in his capacity as a chief recruitment officer for the Galactic Empire, held the naval rank of captain. His role involved enlisting individuals who wished to join the Imperial Armed Forces into the various Imperial Academies.
During his time at Coronet Spaceport in 13 BBY, Munbrin was responsible for recruiting potential candidates for the Empire. One day, a young man named Han expressed his interest in joining the Empire with the goal of becoming the best pilot in the galaxy. Upon inquiring about Han's surname, Han replied that he didn't have one, suggesting to the officer that he was alone in the world. Munbrin then decided to give Han the surname "Solo" and dispatched him to the academy located on Carida.
The account of how Munbrin assigned Solo his surname eventually became widely known. However, a Snivvian bounty hunter considered the story of Munbrin's meeting with Solo to be intentional misinformation. Instead, he theorized that Solo was a direct descendant of Prince-Admiral Jonashe Solo, who was a member of the ancient Corellian royalty. Conversely, an enforcer from Crimson Dawn posited that Solo was the grandson of the Corellian pirate Dalla Suul, and that Munbrin simply misunderstood his surname during the recruitment process.
At some point in time, Ben Solo, Han's son, came to learn the origins of his father's surname. Nevertheless, while in conversation with Snoke following the destruction of Luke Skywalker's Jedi temple, Ben expressed his dislike for the surname and declared that his father was a lie.
Drawd Munbrin's initial appearance was in the 2018 Star Wars Anthology film, Solo: A Star Wars Story, where he was portrayed by Andrew Woodall. Within Star Wars Legends continuity, "Solo" was not a nickname, but rather the actual surname of Han.
The line spoken by Munbrin when giving Han his surname was the very first line that was penned for the film's script in 2012, when Lawrence Kasdan presented the film's concept to Disney CEO Bob Iger a few weeks before The Walt Disney Company finalized its acquisition of Lucasfilm. While in discussion with Simon Kinberg and Michael Arndt, Kasdan shared the idea of the moment Han receives his name and how it all unfolds.
Based on the Imperial rank chart developed by Dave Crossman for use in both Rogue One: A Star Wars Story and Solo: A Star Wars Story, Munbrin would have held the rank of captain within the Imperial Navy.