She is one of a handful of Japanese idol voice actors that rose to prominence in the 2000s, whose popularity today has been attributed to their solid experience and long-term interaction with their fan base, as opposed to the contemporary norms of youth and beauty in the entertainment industry.

[5] As a result of her ongoing success, she has performed solo at large music venues, such as the Nippon Budokan in 2009 and the Yoyogi National Gymnasium's First Stadium in 2015,[4] each with capacities of approximately 14,000 and 13,000, respectively.

Some of her notable roles in anime include Naru Narusegawa in Love Hina, Izayoi Riko/Cure Magical in Witchy PreCure!, Multi in To Heart, Tohru Honda in Fruits Basket, Ai in Dōbutsu no Mori, Ayu Tsukimiya in Kanon, Yuki Cross in Vampire Knight, Hanyuu and Maria Ushiromiya in, respectively, Higurashi When They Cry and Umineko When They Cry, Miss Monochrome in Miss Monochrome, Minori Kushieda in Toradora!, Tsubasa Hanekawa in Monogatari, Chie Satonaka in Persona 4, Kōko Kaga in Golden Time, Carla in Fairy Tail and Wiz in KonoSuba.

[12][13] The following year, Horie succeeded in auditioning for the lead female role of the TV anime adaptation of the shōnen manga comedy Love Hina, as Naru Narusegawa.

[14] The high popularity at the time lead to Lycos Japan using the anime to advertise its search engine and other services, with narration from Horie.

The ascending popularity of Love Hina spawned a lucrative franchise of OVAs, Drama CDs and games, of which Horie reprised the star role.

In regard to their rising fame, Horie worked with Yukari Tamura and form the group Yamato Nadeshiko (やまとなでしこ).

[16][17] Together they would release two singles, "Mō Hitori no Watashi" (もうひとりの私) in 2000 [18] and "Merry Merrily" in 2001, the latter being used as an insert song in the Love Hina Christmas Special.

[16][17] 2000 also saw Horie publish her first photobook, Kingyobachi Puranetto (金魚鉢プラネット, Fishbowl Planet),[20] and the release of her debut album, Mizutamari ni Utsuru Sekai, through the Starchild label which featured two songs from Love Hina.

"Black Cat Alliance"),[21][22] where member benefits included fan events, priority seating in concerts, bimonthly newsletters, and access to exclusive merchandise.

[21] Early in 2002, Horie's first solo concert tour kicked off on January 26 at the Club Diamond Hall in Nagoya, a 1000 capacity venue.

[24] "堀江由衣 First Live Tour", lasted a total of 6 nights, travelling to Tokyo and ending on February 11 in Osaka at the Matsushita IMP Hall.

The 27 minute VHS tape was called Yui Horie CLIPS 0 〜since '00〜'01〜, featuring interviews, making-ofs and notably the music video for "Love Destiny" the theme song of the 2001 anime adaptation of Sister Princess.

[41] Her first appearance was in The Adventure Over Yui Horie III ~Secret Mission Tour~ concert, acting as the antagonist who wanted to turn the world black and white.