Niigaki performed alongside the entire then-ensemble of Hello! Their first single, Bokura ga Ikiru MY ASIA, was released on January 24.
Niigaki continued her career in Morning Musume during 2002 and into 2003. Niigaki also released a joint photobook with the rest of the fifth generation members. Kono Chikyuu no Heiwa wo Honki de Negatterun da yo! She also participated in another drama, Ore ga Aitsu de Aitsu ga Ore de. Wagamama Ki no Mama Ai no Joke / Ai no Gundan | 55. Niigaki also received a part in the movie Tokkaekko alongside other Morning Musume members. Later in September, all of the fifth generation members were placed into subgroups. Egao no Kimi wa Taiyou sa / Kimi no Kawari wa Iyashinai / What is LOVE? Her first appearance on a full-length Morning Musume recording was on the album, 4th Ikimasshoi! In June, she also debuted in a shuffle unit, as part of Happy 7, coincidentally with two other members of her generation (Takahashi and Ogawa). Tsumetai Kaze to Kataomoi / ENDLESS SKY / One and Only | 61.
Niigaki participated in a drama alongside her fellow Morning Musume members, titled Angel Hearts. Brainstorming / Kimi Sae Ireba Nani mo Iranai | 54. Seishun Kozou ga Naiteiru / Yuugure wa Ameagari / Ima Koko Kara | 59.
In October, Niigaki was placed in the unit Athena & Robikerottsu along with fellow Morning Musume member Mitsui Aika, as well as Nakajima Saki and Okai Chisato of ℃-ute.
On April 25, Niigaki released her fourth solo photobook Happy Girl.
Niigaki Risa (新垣里沙, born October 20, 1988 in Kanagawa, Japan) is a Japanese Pop singer and idol managed by J. As of 2009, she was the longest serving sub-leader. On May 18, 2012, she graduated from Morning Musume and Hello! Morning Musume producer Tsunku said he chose Niigaki because she "shined during the final studio recording" for the audition song that all the finalists had to sing. Moonlight ~Ai no Big Band~" alongside her fellow generation members. Sexy Cat no Enzetsu / Mukidashi de Mukiatte / Sou ja nai | 63.
Niigaki was the sub-leader of Morning Musume, inheriting the title from the the former leader Takahashi Ai and was sub-leader until Takahashi's graduation. On January 2nd 2012, it was announced that Niigaki Risa would graduate after Morning Musume Concert Tour 2012 Haru ~Ultra Smart~. Niigaki joined Morning Musume as a fifth generation member along with Takahashi Ai, Konno Asami, and Ogawa Makoto.
On the January 9, fellow 5th generation member Takahashi Ai announced that she would be graduating from the group at the end of their Autumn concert tour, making Niigaki the new leader of the group once Takahashi graduated.