In December 2009, while attending Hyogo Prefectural Itami Nishi High School, Arimura auditioned for FLaMme and passed. In May 2010, she made her first series appearance in Hagane no Onna. Arimura gained popularity by appearing in the Morning dramaAmachan in 2013.[5] Arimura then appeared as the lead actress in the critically acclaimed film Flying Colors where she was cast as a troubled teen who attends a cram school at the behest of her mother in order to gain entry to University. The film was a massive box office success and was the 8th highest-grossing film in Japan in 2015.[6] Arimura was nominated for both the Outstanding Performance By An Actress In A Leading Role and Newcomer of the Year Awards in the 39th Japan Academy Film Prize for her role in the film. She was awarded the Newcomer of the Year Award.
Arimura was selected as the lead actress for the Asadora Hiyokko in the year 2017. For her role in the drama, she was voted as the Best Actress in The 94th Television Drama Academy Awards (2017), an award given quarterly by a popular Japanese magazine, The Television, and are based on the combined results of votes from the magazine readers, juries, and TV journalists in Japan.[7] She has since appeared in many critically acclaimed television dramas and films such as Meet Me After School, I Am a Hero, Cafe Funiculi Funicula and Sekigahara. In the film Sekigahara, Arimura played the role of a ninja named Hatsume who was recruited by the legendary samurai Ishida Mitsunari. The film was nominated for the Picture of the Year award at the 41st Japan Academy Film Prize.
Arimura has also taken on acting roles in works which are regarded as controversial in nature. In the drama Meet Me After School, Arimura took on the challenging role of a young teacher who ended up falling in love with her 15 year-old student. Despite its controversial nature, the drama was named the Best Drama in the 99th Japan Television Drama Academy Awards.[8]
The year 2021 proved to be a very successful year for Arimura. She appeared in the film We Made A Beautiful Bouquet, which was the 8th highest grossing film of 2021 in Japan.[9] Arimura was awarded the Best Actress award in the 45th Japan Academy Film Prize for her role in the film.[10] Arimura also starred in the blockbuster films Rurouni Kenshin: The Final and Rurouni Kenshin: The Beginning, the final 2 films of the epic Rurouni Kenshin film franchise which consist of films which are adapted from the Rurouni Kenshin manga series. Both films were massive box-office successes in 2021 in Japan, grossing more than 6.5 billion yen cumulatively. Arimura portrayed Yukishiro Tomoe, the deceased-wife of the titular character Himura Kenshin. Rurouni Kenshin: The Final was the 6th highest grossing film whilst Rurouni Kenshin: The Beginning was the 13th highest grossing film for the year 2021 in Japan.[11]
On the drama side, Arimura starred as a young lady struggling with employment, who happens to chance upon a group of also struggling stand-up comedians in the 2021 slice of life drama Life's Punchline (Konto Ga Hajimaru). For her role in the drama, she was voted as the Best Supporting Actress in The 108th Television Drama Academy Awards, making her one of the few female actresses who has won both the Best Actress (Hiyokko) and Best Supporting Actress Awards (Life's Punchline) in The Television Drama Academy Awards.[12]
Arimura appeared in the drama Zenkamono (a.k.a Prior Convictions) wherein she acted as a voluntary probation officer who was tasked with the supervision of 3 separate paroled convicts. A movie version of Zenkamono starring Arimura was also released in 2022. Also In 2022, Arimura appeared alongside Ninomiya Kazunari in the TV Special Adventure of Comandante Cappellini (Sensuikan Cappellini-go no Bouken) and starred in the drama Ishiko and Haneo. Arimura appeared in the film Phases of the Moon in December 2022.[13]
In June 2024, Arimura appeared in the film Dear Family as a supporting character.
[14]
In July 2024, Kasumi starred alongside Ren Meguro in the drama Where Does The Sea Begin.[15]
In November 2024, Kasumi appeared in the Netflix-produced drama titled Beyond Goodbye.[16]Beyond Goodbye was ranked the 9th most-watched non-english TV series on Netflix on its first week of airing.[17]
^"有村藍里"架純の姉"バレて世間から猛バッシング 引退よぎるも…本名での活動決意させた妹の助言" [Airi Arimura, "Kasumi's sister" revealed and heavily criticized by the public; she considered retiring but her sister's advice made her decide to continue working under her real name]. Sponichi Annex (in Japanese). May 29, 2022. Archived from the original on March 18, 2023. Retrieved September 28, 2022.