Yahagi is best known for her role as Kotoko Aihara in Mischievous Kiss: Love in Tokyo and its sequel Mischievous Kiss 2: Love in Okinawa as Kotoko Irie.

She's also known for portarying Mezool in the tokusatsu series Kamen Rider OOO.

Yahagi was born on 7 March 1997 in Chiba Prefecture, Japan.

In April 2009, Yahagi began working as an exclusive model for teen fashion magazine Love Berry.

Yahagi's special skills include classical ballet and her favorite musical group are NEWS and TVXQ In 2016, Yahagi changed her artist name from Honoka Miki to her birth name Honoka Yahagi because she wanted to honor the name she received from her parents.