Born in 1723 as a physician of the Nakatsu domain in Buzen. Drawn to Rangaku from his youth, at 47 he became a disciple of the Rangaku pioneer Aoki Kon'yō and began serious study of Dutch, later deepening his language skills through study in Nagasaki. In 1771 he attended the dissection of an executed criminal at Senju Kotsukahara in Edo and was struck by the precision of the Dutch anatomical treatise Ontleedkundige Tafelen (Tabulae Anatomicae). From the next day he began translation work with Sugita Genpaku and Nakagawa Jun'an, publishing Kaitai Shinsho in 1774 after four years of struggle. Ashamed of the imperfections of his translation, Maeno had his name removed from the cover, which bore Genpaku's alone. He went on to devote himself to Rangaku research, expanding his vocabulary self-taught throughout his life. He died in 1803 at 81.

Earnest and perfectionist. He was too fastidious to lend his name to work he considered incomplete, yet also a passionate late learner who began studying a foreign language at 47 — the very image of the ideal Edo intellectual who renounces fame and gain for the sake of scholarship. He is said to have been taciturn, the type who buries himself alone in his studies.

Kaitai Shinsho marked a turning point as the first substantive introduction of Western medicine to Japan and laid the foundation for all later development of Rangaku and medicine. Many medical terms still in use — shinkei (nerve), nankotsu (cartilage), dōmyaku (artery) — were coined by Maeno, Genpaku, and their colleagues. Because Genpaku explicitly identified Maeno as the lead translator of Kaitai Shinsho in his Rangaku Kotohajime, posterity came to give his achievement its proper due. He is being increasingly reappraised as one of the quieter but most important figures in the history of Rangaku.