2007–2008: Debut and Girl's Generation

In July 2007, Girls' Generation had their unofficial first stage performance on Mnet School of Rock where the group performed their first single, titled "Into the New World" (다시 만난 세계, Dasi Mannan Segye). A documentary recording the story of the group's debut titledMnet Girls' Generation Goes to School was filmed during this time, showing the members as they moved into an apartment together and prepared for their performances. The group's first single was physically released soon after, including an instrumental of the group's debut song and two other tracks: "Beginning" and "Perfect for You." The latter's Korean title is "Wish" (소원, SoWon), which later became the name of Girls' Generation's official fan club, S♡NE. The group's debut officially began on August 5, 2007, first performing onSBS Inkigayo, later on MBC Music Core and KBS Music Bank. "Into the New World" achieved No.1 spot on M! Countdown.

The group released their first self-titled full album in late autumn of 2007 with the lead single "Girls' Generation" (소녀시대, Sonyeo Sidae), a remake of Lee Seung-cheol's 1989 song. Promotion for the single started in early November. The album also included the group's first single "Into the New World", "Perfect For You" (re-titled "Honey"), and eight other tracks by the group. In early 2008, Girls' Generation began promoting their second single from the album, "Kissing You", which won the group their first K-chart win after achieving the number one position on the KBS Music Bank February chart.

In March 2008, the album was repackaged, re-released and re-titled Baby Baby. A third single, "Baby Baby", was released to promote the album. During the group's promotions, members Jessica, Tiffany and Seohyun were featured on a mini-album released by Roommate, a one-man band from Purple Communication. The mini-album was titled Roommate: Emotional Band Aid, and was released on December 1, 2008. The song performed by the three girls, titled "Oppa Nappa" (오빠 나빠; literally, Bad Brother), was digitally released before the album in April 2008. The song was performed live on SBS Inkigayo, KBS Music Bank, and M! Countdown.Later in the year, the three members released "Mabinogi" (It's Fantastic!) together as the theme song for the Nexon game Mabinogi, with Tiffany participating in the music video.^[12]

Mnet reality show Factory Girl chronicled the members working as interns at fashion magazine Elle Girl. The program began airing in early October.^[14] In late 2008, the group also participated in the SM Town Live '08 concert along with other SM Town artists.