Hiroko Kasahara is a Japanese voice actress, singer, and stage actress born on February 19, 1970, in Tokyo. She began her career in entertainment at the age of five, joining the theater group剧团こまどり (later known as Group Komadori) to help build her confidence. Her voice acting debut came in 1983 at the age of thirteen, when she was cast as Kachua Pearson in the television anime series Ginga Hyōryū Vifam. As a student, she chose voice acting because it allowed her to work without appearing on screen, which was against her school's policies on entertainment activities.

In addition to her voice work, Kasahara developed a parallel career as a singer. Her debut as a singer came in 1986 with the song Kokuhaku ~Itoshi no Jose from an image album for the manga Champagne Shower. Her clear and strong singing voice earned her the nickname "Utahime" or "Diva of the voice acting world". She performed theme songs for several series in which she acted, such as Mahou no Angel Sweet Mint, and also contributed music to projects where she was not a cast member, like the opening theme for Mobile Police Patlabor: The Early Days and the ending theme for the anime Romeo's Blue Sky.

Kasahara's career is marked by a wide variety of notable roles across anime, OVAs, and video games from the 1980s through the 2000s. One of her earliest leading roles was as the titular character Mint in the 1990 magical girl series Mahou no Angel Sweet Mint. In 1991, she voiced the refined Nanako Misono in the acclaimed drama Dear Brother. She played the magical songstress Ishtar in the 1992 OVA The Super Dimension Fortress Macross II: Lovers, Again. A significant and popular role came in 1994 when she was cast as the kind and intelligent Fuu Hououji, one of the three Magic Knights, in the series Magic Knight Rayearth. Her other prominent anime roles include Princess Camille in the 1989 film Little Nemo: Adventures in Slumberland, Azalyn in The Irresponsible Captain Tylor, Ami in DNA², and Sayo Magdalia in Rurouni Kenshin.

Kasahara also built a substantial body of work in OVAs, which were a major part of the anime industry during the late 1980s and 1990s. Examples of these roles include Maron Namikaze in Assemble Insert, Laura Sullivan in God Bless Dancougar, Ryo Narahara in Megazone 23 Part III, Sango Otojima in Kyūkyoku Chōjin R, and G2 in Don't Leave Me Alone, Daisy. In the 2000s, she continued to work, taking on roles such as Mariel-hime and Mau in Yamibo - Darkness, the Hat, and the Travelers of the Books, Amy Kashihara in Shin Megami Tensei Devil Children, Hazuki Koyama in Full Moon o Sagashite, and Newtar in Master of Epic: The Animation Age. She has also had a long-running association with the character Tama from the San-chōme no Tama franchise, voicing the role in multiple series and films from 1988 to 2019.

Kasahara has been represented by the agency Ogipro The Next. Throughout her long career, she has maintained close friendships with fellow voice actors from her time at Group Komadori, including Mina Tominaga, Nariko Fujieda, and Maaya Sakamoto.