大阪府出身、わがままヴォイスが魅力のシンガーソングライター。
代表曲「たばこ」をはじめ、近年では「♡人生♡」「元彼女のみなさま」などヒットを連発。楽曲提供をした「最上級にかわいいの！」では日本レコード大賞作詩賞を受賞した。
2025年3月19日に4年ぶりに4th Full Album「あたしを選んだ君とあたしを選ばなかった君へ」をリリース。5月からスタートする全国ツアー「コレサワ LIVE TOUR 2025 あたしを選んだ君と行くツアー」は全公演チケットが完売。追加公演として9/16(火)に初の日本武道館ライブ「あたしを選んだ君と行く武道館」の開催が決定！10月からは全国10か所の追加ツアーも行われる。
メディアには顔だしはせず、素顔が見れるのはLIVEのみで、「れ子ちゃん」と言われるクマのキャラクターがビジュアルを担当する。

A singer-songwriter from Osaka, known for her charming "selfish voice."

Her signature song, "Tobacco", has been followed by a string of hits in recent years, including "♡My Life♡" and "Dear ex-girlfriends" She also won the Japan Record Award for Best Lyrics for the song "Super cute!", which she wrote.

On March 19, 2025, she released her 4th full album, "Atashi wo Eranda Kimi to Atashi wo Erabanakatta Kimi e," marking her first album in four years. Her nationwide tour, "Koresawa LIVE TOUR 2025 – Atashi wo Eranda Kimi to Iku Tour," kicks off in May and has already sold out in all venues. Due to high demand, an additional show has been announced—her first-ever Nippon Budokan concert, "Atashi wo Eranda Kimi to Iku Budokan," on Tuesday, September 16. In addition, she will begin an extra 10-city tour starting in October.

Koresawa never reveals her face in the media, and the only place to see her
true self is at her live performances. Instead, her visual identity is
represented by a bear character named "Reko-chan."