Following graduation from McKinney High School in 2003,[2] Lang played golf at Duke University for two years and won six collegiate tournaments.

Lang was also a member of the victorious Curtis Cup team in 2004 and won medalist honors at the U.S. Women's Amateur Public Links, where she advanced to the quarterfinals of match play.

While still an amateur in 2005, Lang competed as a sponsor's exemption in both the Kraft Nabisco Championship and the LPGA Corning Classic, where she tied for 15th.

After two years of college golf at Duke, Lang turned professional in July 2005, shortly after her T2 finish at the U.S. Women's Open.

Lang's first professional win came in June 2012 at the inaugural Manulife Financial LPGA Classic in Canada, where she triumphed in a four-player playoff.