[7] In 2008, Nihon Monitor recognized Horikita as one of Japan's top endorsers during its annual Most Popular Personality in TV CMs.

[8] Horikita had been cast in several drama series and movies since 2003 but her roles in Densha Otoko and Nobuta wo Produce became her breakthrough performances.

[10] Towards the end of the year, she had been cast as Naomi, the female protagonist of Dareka ga Watashi ni Kiss wo Shite or DareKiss (based on Gabrielle Zevin's popular novel, Memoirs of a Teenage Amnesiac) a Hollywood-Japan collaboration film directed by internationally acclaimed director and self-confessed Japanese culture fanatic Hans Canosa.

[12] As soon as the filming for DareKiss ended, Horikita had gone on to appear in two television dramas: Atashinchi no Danshi in 2009 as an adoptive mother of six young men (played by Jun Kaname and Mukai Osamu among others) and Tokujo Kabachi!!

[15] The morning drama featured Horikita as Umeko Shimomura in her carefree teenage years until she blossomed into a dependable town doctor during the Showa era.

[1] After the success of her asadora, Horikita has continued accepting lead roles in more television and movie projects like in the evening dramas Miss Pilot in 2013 and Masshiro in 2015 as well as in the film Mugiko-san to in 2013.

When she was the host, Horikita provided book recommendations to her listeners and called selected letter-senders to discuss the questions they wrote in their letters.

She took turns with Erika Toda, Yui Aragaki, Chiaki Kuriyama, Nana Eikura, and Kii Kitano until she left the program in 2009.

[21] The couple became close in May 2015 when playing the role of lovers in the theatrical production Arashi ga Oka (Wuthering Heights) and had commenced dating in June.