Yoshinaga debuted in 1994 with The Moon and the Sandals, serialized in Hanaoto magazine, but was previously a participant in comic markets. Of Yoshinaga's many works, several have been licensed internationally. She was also selected and exhibited as one of the "Twenty Major Mangaka Who Contributed to the World of Shojo Manga (World War II to Present)" for Professor Masami Toku's exhibition, "Shojo Manga: Girl Power!" at CSU-Chico. Outside of her work with Japanese publishers, she also self-publishes original doujinshi on a regular basis, most notably for Antique Bakery. Yoshinaga has also drawn fan parodies of Slam Dunk, Rose of Versailles, and Legend of Galactic Heroes. Although little is known about Yoshinaga's personal life, she mentions that her favorite operas are those by Mozart in the author's note to Solfege. In an interview, she has said that "I want to show the people who didn't win, whose dreams didn't come true. It is not possible for everybody to get first prize. I want my readers to understand the happiness that people can get from trying hard, going through the process, and getting frustrated."