Oh Ha-young was revealed as a member of the girl group A Pink on February 21, 2011 via Twitter. On April 21, 2011, she made her debut with A Pink on Mnet M! Countdown with their first single, “I Don’t Know”. A Pink has released one studio album and four EPs.
In 2010, Oh made a cameo in the music video for boy band Beast‘s song “Beautiful”.
In July 2012, she appeared in the music video for Mario’s song “Mayday” along with other members of A Pink.
On July 30, 2014, Oh featured in music video “The Best Thing I Did”, the title track for Jiggy Dog’s third mini-album.