AKB48 Watanabe auditioned for
AKB48's 3rd generation and was placed in the newly formed Team B, serving as a key memberof the group. Her selection on "
Bingo!" marked the first appearance of a Team B member in an AKB48 single title track. She would go on to appear on all of the a-side tracks for AKB48's singles until her graduation, with the exception of line-ups determined by
rock-paper-scissors tournaments. In 2009, Watanabe placed fourth overall in the group's first general election to determine the line-up for the group's 13th single, and ranked fifth the next year for the group's 17th single. Watanabe appeared on the cover of the December 2010 issue of
UP to boy magazine together with
Airi Suzuki from
Cute. It was the first
gravure collaboration between
Hello! Project and AKB48. On May 13, 2011, Watanabe released her first
photo book,
Mayuyu. She commented that the book "is filled with a lot of expressions that I haven't shown until now, it's a book I'm really pleased with!" Regarding her cover picture, she said, "Despite being embarrassed, I did my best on the front cover, so I want a lot of people to look at it!" For AKB48's general election in 2011, Watanabe placed fifth overall. In 2012, Watanabe played her first lead role in the Japanese TV drama
Saba Doru, where she played a 38-year-old high school teacher hated by her pupils, whilst having a hidden life as the highly popular idol Mayu Watanabe, based on her real-life self. On February 29, Watanabe released her debut solo single, "
Synchro Tokimeki", which was also the opening theme for the drama. Watanabe participated as a voice actress in the anime series
AKB0048. In the anime, she plays a main character
Chieri Sono, and is part of the AKB48 subgroup
NO NAME, which sings the opening and ending themes for the series. The series features a supporting character,
Mayu Watanabe Mark 3, which is modeled after her likeness, and is voiced by
Yukari Tamura. She reprised her role as Chieri Sono for the series' second season which aired in 2013. Watanabe ranked second overall in the 2012 AKB48 general elections with 72,574 votes. On August 24, she was moved from Team B to Team A during AKB48's reorganization announcement at their
Tokyo Dome concert. On July 25, she released her second solo single, "
Otona Jellybeans" which reached number three on the Oricon weekly chart. Her third solo single "
Hikaru Monotachi" was released on November 21, 2012, and reached number one in the Oricon singles chart. The single was released in five versions, including one that has an illustration book. Its b-side "Sayonara no Hashi" is the theme song to the anime film
Nerawareta Gakuen for which she voiced one of the lead characters. In July 2013, she released her fourth solo single, "
Rappa Renshūchū". A contest was held to determine the cover artwork for one of its editions. Meanwhile in AKB48, she received her first center position with the group's 30th single "
So Long!", which was released on February 20, 2013. On April 19, she released her second photobook
Seifuku Zukan Saigo no Seifuku. In the AKB48 election for the members for their 32nd major label single, she placed third overall with 101,210 votes. In 2014, Watanabe became a regular on the television show
Utage!, and a semi-regular on the TV show
Renai Sosenkyo. In AKB48, she was transferred back from Team A to Team B in the "Daisokaku Matsuri". She performed an hour-long solo live concert at AKB48's Natsu Matsuri. She earned the center position for AKB48's 37th major label single, "
Kokoro no Placard" after placing first with 159,854 votes in an election to determine the single's member line-up. In 2015, Watanabe received her first leading role in a prime-time TV drama,
Tatakau! Shoten Girl, broadcast by
Fuji TV and
Kansai TV. This drama aired from April 2015, at 10 pm. The theme song for this drama, "
Deai no Tsuzuki", was sung by Watanabe, and was also released as her fifth solo single on June 10, 2015. She held solo live concerts to support the single on September 19. In 2015, a web poll conducted by My Navi Student declared her the second cutest idol amongst both men and women, behind
Kanna Hashimoto of the idol group
Rev. from DVL. On October 26, 2016, Watanabe released her third photobook
Shiranai uchi ni. On October 31, Watanabe had her graduation concert. Her last handshake event with the group was on November 18, while her last performance at the AKB48 theater was on December 26. Her last activity as an AKB48 member was a performance at the "68th
NHK Kouhaku Uta Gassen" on December 31, 2017.
AKB48 General Elections Her results in the annual ranking: • Ranked 4th in the 2009 General Election (1st) • Ranked 5th in the 2010 General Election (2nd) • Ranked 5th in the 2011 General Election (3rd) • Ranked 2nd in the 2012 General Election (4th) • Ranked 3rd in the 2013 General Election (5th) • Ranked 1st in the 2014 General Election (6th) • Ranked 3rd in the 2015 General Election (7th) • Ranked 2nd in the 2016 General Election (8th) • Ranked 2nd in the 2017 General Election (9th)
Post-AKB48 In January 2018, it was announced that Watanabe would play the titular character in the Japanese production of the
Amélie adapted from
the movie of the same title. The production ran from May 18 to June 3 at the Galaxy Theater in
Shinagawa,
Tokyo, and June 7–10 at the Morinomiya Piloti Hall in
Osaka. In April 2018, Watanabe had her first drama post-AKB48 titled where she played an insurance investigator. In August 2018, Watanabe starred in the special drama , a continuation from the same series in 2017. Following two special dramas, Watanabe then had the lead role in a late-night drama in August 2018. Her character, Hikari, was a girl whose dream was to become a musical actress, but got her dreams smashed when her brother supposedly committed murder. In late 2018, Watanabe also endorsed the
brand Yakult. The commercial was directed by Ikeda Kazumasa who has directed music videos for Keyakizaka46 and Nogizaka46, while choreography was by Sasao Isao who choreographed one of Keyakizaka46's singles. The commercial also features some 33 professional dancers and performers including Spinboy Aichi, SORI and HICKY of the dance team SHIFFLE!! among others. Watanabe also guested several music shows, namely Utacon and UTAGE. In Utacon, she sang musical songs, including collaborations with several famed musical actors. Towards the end of 2018, Watanabe was named the ambassador for
JAL Honolulu Marathon. On June 1, 2020, Production Ogi announced her retirement from the entertainment industry for health reasons. Her website was terminated amicably on the same day. == Personal life ==