In 2009, Miyazato recorded a career-best fourth place finish at the LPGA Corning Classic, where she carded a career-low 62 in the third round; also tied for fourth at the Wegmans LPGA and was sixth at the Honda LPGA Thailand.
In 2010, Miyazato recorded the first victory of her career at the Japan Women's Open on the JLPGA, winning by a comfortable margin of 6 stokes. She also managed impressive performances on the LPGA tour where she finished third at the P&G NW Arkansas Championship Presented by Walmart and tied for third at the Sime Darby LPGA Malaysia.
2011 saw Miyzato finish a season’s best fifth place at the US Women's Open. In 2012 she claimed the Safeway Classic and crossed $1 million mark in a season for the first time in her career.