Kato was born on July 10, 1997, in
Chiba Prefecture, Japan. As a child, she appeared in many magazines as a model, and subsequently joined AKB48, aspiring to become a famous model someday. She joined AKB48 to pursue that dream, with the encouragement of her friends. Kato participated in the 10th-generation auditions held by AKB48, and joined as a
kenkyuusei trainee in March 2010. She officially participated on AKB48 singles on
Chance no Junban's coupling song, titled "Fruits Snow", as part of Team Kenkyusei. On December 17, 2011, Rena Katō, together with two other members of AKB48,
Ami Maeda and
Anna Iriyama, held a large autograph-signing event in Hong Kong. At the end of 2011, while still an AKB48 trainee, she appeared on the cover of the Japanese magazine
Weekly Playboy with seven other top members of AKB48 and SKE48. It was the last issue of 2011. In 2012, she participated in the AKB48 drama
Majisuka Gakuen 3, which was a sequel to the series, but with a different storyline completely unrelated to the previous adaptations. She was also promoted to Team 4 on March 23, 2012. Soon after the TV series
Shiritsu Bakaleya Kōkō ended on June 30, 2012, it was announced that Rena Katō would participate in its film adaptation. The series and movie starred several
Johnny's Jr. and AKB48 members. She participated on her first A-side in AKB48 on the summer single titled "Manatsu No Sounds Good!". She was transferred to Team B after the AKB48 Tokyo Dome Shuffle on August 24, 2012, where her then-team, the first version of Team 4, was disbanded. In 2013, she participated in her second A-side in AKB48 on the summer single "Sayonara Crawl", which included 38 members. She got her first center song in "Heart Electric", the 33rd single's B-side, "Kaisoku To Dotai Shiryoku", as the center of Undergirls, a duo center with SKE48 member Suda Akari. In 2014, she got a knee injury and had to temporarily postpone her AKB48 activities, as a result, she was not able to participate in the Unit Matsuri 2014, as well as the AKB48 Request Hour Set List Best 200, except on the final day. Even with an injury, she and
Yuki Kashiwagi held a large autograph-signing and handshake event in Hong Kong with thousands of fans. She resumed her activities on February 16, 2014. She was transferred back to Team 4 during the AKB48 Group Daisokaku Matsuri. She joined the Senbatsu for the third time in the 37th single's A-side, titled "Labrador Retriever", released on May 21, 2014. On March 26, 2015, she was transferred back to team B in
the AKB48 Spring Shuffle 2015 event. From 2015 to 2017, Kato held annual contests called , inspired by the AKB48 Group's
Senbatsu Sōsenkyo. It started when Kato made a list of her favorite members on social media at her fans' request, but received the approval of
Yasushi Akimoto shortly after and eventually became an official event. Every year, AKB48 Group members can apply for the opportunity to take part in singles, photoshoots, and theatrical productions organized by her. Despite the name, the winners are decided by Kato and her team instead of by
election. On December 16, 2021, during a
YouTube livestream, Kato announced her graduation from AKB48 to pursue a career as a
beautician. Her last theater performance was on February 14, 2022, and her final group activity was on February 20. Her official fanclub, "Rena's dresser", was launched on March 1, 2022, 9 days after graduating from AKB48. On September 30, 2023, Kato announced via Instagram that she had obtained a beautician's license. On April 14, 2024, Kato opened a second Instagram account that focuses on her hair and makeup career. == Personal life ==