She rose to prominence for her portrayal of Luna Lovegood in the Harry Potter film series, appearing in the last four films and their tie-in video games, as well as in the musical A Very Potter Senior Year.
In 2012, she told Charlie Rose that when composing the final books, "I saw her. I even heard her voice when I was writing Luna." The film was cancelled due to problems with funding. In May 2013, it was announced that Lynch was to star in the British stage tour production called Houdini which performed at various theatres in the United Kingdom from 9 September 2013 to 12 October 2013.And then all these camera people starting coming into the school and all the other girls were outside waving and I stayed inside and they didn't notice me.I think they had dyed my hair at that point so it was different and I had to have security people.[September 2006]Her father flew her to London to the open audition for the part of Luna Lovegood in Harry Potter and the Order of the Phoenix (2007).Her mother did not believe she had much of a chance of winning the role so initially refused to let her apply.
Harry Potter and the Order of the Phoenix, Harry Potter and the Half-Blood Prince, Harry Potter and the Deathly Hallows – Part 1, Harry Potter and the Deathly Hallows – Part 2, G. F., Addiction: A 60's Love Story, My Name Is Emily, Monster Butler, Houdini[about acting with the other cast] It was this feeling the whole time like I shouldn't be here among all these stars and professionals.