Jonathon Ha is a Korean-American voice actor and performer who has become active in English-language dubbing of anime and animated series. His entry into the voice acting industry began from a non-traditional background, having originally studied film production and worked as a video editor in the K-pop industry. Ha has described himself as a shy individual who suffered from stage fright, though he developed a passion for music performance during his school years, playing in marching, concert, and jazz bands for nearly a decade. The COVID-19 pandemic prompted him to explore voiceover work out of curiosity, eventually leading him to take over seventy acting classes in two and a half years. He signed with the agency CESD Talent in February 2024.

Ha has stated that his musical background helps him analyze voice performances in terms of cadence, pitch, and rhythm, while his film education provides an understanding of visual storytelling that he applies to his vocal work. He contributed background voice work, referred to as looping, to the Sony Animation film K-Pop Demon Hunters, which he has discussed as a significant early project.

In the English dub of the anime series Disney Twisted-Wonderland The Animation: Episode of Heartslabyul, Ha voices the protagonist Yuken Enma, a young man from Japan who becomes the groundskeeper at the mysterious Night Raven College after being unable to return home. The English adaptation features Ha alongside voice actors such as Paul Castro Jr. as Riddle Rosehearts and Max Mittelman as Ace Trappola.

Ha has multiple roles in the Digimon franchise entry DIGIMON BEATBREAK. He voices Genjo Kanada as part of the Five Stars group, as well as the Digimon characters Ludomon and Gigasmon, who are partners within the Tactics group. He appears alongside returning cast members including Paul Castro Jr. and Kira Buckland in this production.

Additional voice roles for Jonathon Ha include Tsukasa Akeuraji in the English dub of Medalist, a character originally voiced in Japanese by Takeo Ōtsuka. He plays Takeshi Hirano in the 2025 remake of Cat's Eye. In the dance-themed anime Wandance, he voices the character Seiya. For the supernatural comedy series Witch Watch, Ha provides the voices for both Daiki Sakai Mk. II, a student council member who wears a cardboard robot helmet, and Rui Fujiki, the student council president whose powers reference the Jekyll and Hyde concept. His other anime credits include Shinaya in Sakamoto Days, Byte in Beyblade X, and Usui Uonuma in Rurouni Kenshin -Kyoto Disturbance-.