Balthier was designed by Akihiko Yoshida, who has stated that the character is his favorite from Final Fantasy XII since the character is based on "someone I admire." Balthier has been called a "completely original character" by Yoshida, having not used any previous Final Fantasy character as a reference. In an interview, Yoshida stated that all the characters of Final Fantasy XII were designed with a focus on creating an aesthetic found nowhere in the real world. The armor of the Judges, which Balthier had been, were designed as a combination of historical armor, mountain bike gear, and futuristic ideas. During the making of the game, there were some issues with the character's faces; In one scene Balthier asked Vaan how he was feeling which brought laughter to the staff because in that scene Vaan's face was poorly modelled. In retrospective, Square Enix members found Balthier as an appealing character and jokingly stated Vaan would need an entire decade to surpass him. Balthier was also meant to appear in another Final Fantasy XII game where the character would appear within the game's climax to assist its protagonists, Ashe and Basch, but the game was cancelled.
For Final Fantasy XII, Balthier was voiced by Gideon Emery in English and Hiroaki Hirata in Japanese. Emery commented that while voicing the character of Balthier, he developed a "small crush" on Fran, Balthier's partner. He also commented that the biggest challenge of voicing Balthier was having to stay consistent, adding that he spent more than four hours in a small booth while doing the voice, which could cause him to "drift away from the character" if he goes on for too long. He also described him as being similar to the character. Emery auditioned for Balthier, seeing him after he did this and "instantly fell in love with the character". He described him as a cross between Han Solo, James Bond, and Jack Sparrow, citing suave yet cocky attitude. He was thankful that he was not aware of Balthier's popularity since his reveal, stating that he would have been "crippled by the fear of not delivering on what the fans expected". He stated that he took no inspiration from anyone else for the role, wanting to ensure that he was unique. Instead, he cited the pictures and animation of the character as his inspiration. Emery cited Jack Fletcher, the voice director, as a great help in voicing the character and setting up the scene for him. To give Final Fantasy XII a Western feel, Balthier's movements were recorded by a Western motion capture actor.
Balthier is a Hume sky pirate who pilots the Strahl, a small
airship, around the skies of Ivalice. VideoGamer.com editor Greg Vallentin made a similar comparison, calling him a "Han Solo-like sky pirate". 1UP.com editor Jeremy Parish compared Balthier to Albus, one of the characters from Castlevania: Order of Ecclesia, stating that they share a physical resemblance.