Kwok was born in Laguna Hills, California by a Hong Kong father and an American mother, giving him a distinct, blond-haired and blue-eyed feature, and a dual residential status [REF].
Kwok attended Laguna Hills High School, where he played for the swimming team, and achieved senior national marks in the 200 and 400 m individual medley, and in the long-distance freestyle (400 and 1500 m).