Gu Hara joined the South Korean girl group Kara in 2008 after the departure of its original member Sunghee. Her first album with the group is the extended play Rock U released in July 2008. In July 2009, the group dropped their second studio album Revolution, which produced the hit single Mister. In November 2010, they released their debut Japanese album Girl’s Talk, which sold over 100,000 copies in its first week. Japan’s Oricon named the group as 2010’s Best Rookie Artist. In 2015, Gu Hara released her debut solo extended play Alohara (Can You Feel It?), which reached number 4 on South Korea’s Gaon Weekly Albums Chart.

In 2009, Gu Hara became a cast member of the KBS2 reality show Invincible Youth, which earned her the Best Female MC Award at the KBS Entertainment Awards. In 2010, she made her acting debut in the hit SBS series City Hunter, which won her Best New Actress at the SBS Drama Awards.

In September 2018, Gu Hara and her ex-boyfriend, hairstylist Choi Jong-bum, got into a physical altercation. Both parties alleged each other of assault, with Gu Hara claiming that Choi Jong-bum also blackmailed her with a sex tape. Gu Hara received a suspension of indictment while Choi Jong-bum went on trial. On November 24, 2019, Gu Hara was found dead at her Cheongdam-dong home in an apparent suicide. In 2020, Choi Jong-bum was given a final jail term of one year for assault and threatening.