Jung Hoo Lee is a left-handed outfielder from Korea. He's played for the Kiwoom/Nexen Heroes of the KBO for the past seven seasons. He's known for his glove and is a high-average/high-OBP hitter. His career line is .340/.407/.491 (884 G, 3947 PA) and he turns 26 in August.
The Giants signed Lee to a six-year, $113M deal. That should beef up the outfield!
Wikipedia lists him as Jung-hoo Lee but all the baseball sites list him as Jung Hoo Lee. I suppose rendering Korean names into American English could have a few quirks.