Moon's career breakthrough came with leading roles in the television period drama The Princess' Man (2011) and the action blockbuster War of the Arrows (2011); both of which were critical and commercial hits.

[3] Moon made her acting debut in 2007 in Mackerel Run, alongside fellow newcomer Lee Min-ho; they were among 60 actors who auditioned for the teen sitcom.

Afterwards, Moon landed her first leading role in It's Okay, Daddy's Girl, playing an immature daughter who transforms into a mature professional woman after a family tragedy.

[13] In 2011, Moon was offered the sole female role in War of the Arrows, an action blockbuster set during the Second Manchu invasion of Korea.

Moon was praised for her portrayal of a feminine yet feisty woman abducted by a foreign army on her wedding day, yet who isn't a typical damsel in distress and instead survives by her wits and sheer will.

[15][16] Moon returned to the small screen in the Joseon-era drama The Princess' Man, about a fictional forbidden romance between the daughter of Grand Prince Suyang and the son of Kim Chongsŏ (played by Park Si-hoo), whose fathers were real-life political enemies.

She drew praise for her performance as a cold, cynical woman groomed to take over her father's conglomerate, who later reverts to helpless innocence after losing her memory.

[25] To prepare for her role as pediatric surgeon, Moon met with real-life doctors in a hospital setting, familiarizing herself with medical terms and observing surgeries first-hand.

[30] Moon returned to the big screen in a 2015 romantic comedy directed by Park Jin-pyo, which reunited her with previous Brilliant Legacy costar Lee Seung-gi.

[35] She then starred opposite Yoo Yeon-seok in Mood of the Day, in which they play two strangers who meet on the KTX and spend 24 hours together in the unfamiliar city of Busan.