She began to teach herself how to play the guitar after she entered high school, but gave up and paid for professional lessons after discovering she wasn't making much progress on her own.

Despite this, Miwa secretly worked and eventually used these savings by her second year of high school to buy a Gibson J-45 guitar.

During this time, Miwa released two self-published independent singles, "Song for You/Today" and "Soba ni Itai Kara" in 2007 and 2008.

[8] Her debut single "Don't Cry Anymore" was chosen for the drama Nakanai to Kimeta Hi's theme song.

[13] For the animated film adaptation of Eto Mori's novel Colorful, Miwa covered two songs by famous Japanese artists.

[14] Miwa considers her favorite Western musicians to be Sheryl Crow, Deep Purple, Carole King, Avril Lavigne and Taylor Swift.

[17] It has since then been changed into a weekly show, now known as miwa no All Night Nippon (Miwaのオールナイトニッポン), airing every Tuesday (early Wednesday) from 1:00 am to 3:00 am.