Yoshino holds the rank of Master Sergeant in the Magical Girl Special Operations Development Unit (M-Squad), a Japan Self-Defense Forces anti-magic and anti-terrorism task force commanded by Colonel Yoshiaki Iizuka. This unit operates from a base concealed as Maid Cafe 'Mitsuya'. Within M-Squad, Yoshino works alongside military colleagues and magical girls like Asuka Ootorii and Kurumi Mugen, engaging in magical warfare and counter-terrorism operations.

He blends military professionalism with a laid-back, humorous personality. Yoshino embraces his cover role as chef at Maid Cafe Mitsuya, demonstrating culinary creativity by preparing meals from unconventional ingredients such as snake. Despite his relaxed demeanor, he exhibits significant combat proficiency, specializing as a sniper. His skill earned him victory in the Sniper Aggregate International competition at the AASAM international shooting event.

A distinctive physical trait is that his eyes remain closed throughout the entire franchise. Information regarding his background, chronological development across media, or involvement in story arcs beyond his established M-Squad role is unavailable in the provided sources.