Yoo turned professional in November 2004 and began playing the
Futures Tour in 2005. Yoo won her first professional event, the
Betty Puskar Golf Classic. That and ten top ten finishes in 18 events allowed Yoo to begin playing the
LPGA Tour in 2006. In September 2009 Yoo had her best ever finish on the LPGA Tour. At the end of 54 holes at the
P&G Beauty NW Arkansas Championship, she was tied for first with
Jiyai Shin and
Angela Stanford. A sudden death playoff followed which was won on the second extra hole by Shin. Yoo won her first LPGA Tour title at the 2010
Sybase Match Play Championship where she again faced
Jiyai Shin and
Angela Stanford on the way to the title. She defeated world number one Shin, in a semifinal match 2&1 and went on to defeat Stanford 3&1 in the championship match. On 1 April 2012, Yoo won her first major title, the
Kraft Nabisco Championship.
I.K. Kim had a one-foot putt on the final hole for the win but missed it, resulted in a tie with Yoo and a sudden death playoff. On the first hole of the playoff, Yoo won with a 20-foot birdie putt. Among her fellow South Koreans on the LPGA Tour, Yoo is known as 'Course Clown'. ==Professional wins (3)==