Paul was born in Hollywood California. His parents, Paul Sr. and Nancy, immigrated from South Korea to Los Angeles in the mid 1960's where they owned and operated a convenient store for more than 40 years before finally retiring in 2009. At the age of 11, Paul took an Intro to Drama Class. His first game/activity was playing with sock puppets and created various voices and characters to match the puppets he operated. It was then that the acting bug took it's hold. Later, he booked his very first audition for the acclaimed television series Life Goes On, created by Michael Braverman. Unfortunately, a couple days before filming was set to commence, the part Paul booked was written off. Determined not to be discouraged, Paul applied to and auditioned for the Los Angeles County High School for the Arts. There he won an Arts High Image Award and received a Scholarship from The Dorothy Chandler Foundation for overall excellence. It was also at the High School for the Arts that he met Oscar Nominated Actor and Writer Chazz Palminteri, thanks to Paul's acting instructor, Norman Cohen. It was Mr. Palminteri who told Paul, "If you love acting then don't ever give up." A few weeks later Mr. Palminteri even set up an audition for Paul to try out for a role in Palminteri's A Bronx Tale. Mr Palminteri's advice and generosity still resonates with Paul today.

He enrolled at UCLA and was accepted into the Specialized Acting Track headed by Gil Cates, with faculty that included Ellen Geer, Salome Jens, Gary Gardner and Mel Shapiro. Soon after graduating from UCLA, Paul auditioned for the Cirque du Soliel show "O." After a grueling 10 hour day of auditioning that incorporated his physical skills in Commedia dell'arte and mime, he made the list of finalists... only to be cut because he did not know how to swim, and that "O" was an aquatic show.

However, when one door closes another door opens. Soon after Paul was cast as Yoshi Araki in Mark Romanek's feature film directing and writing debut, One Hour Photo, starring Oscar Winner Robin Williams. While on set of OHP, Director Mark Romanek told Paul that they searched far and wide to cast the role of Yoshi. They auditioned hundreds of candidates, and that Paul was the only one perfect for the role. Soon after the release of OHP, Sheila Benson in an April 2003 article of Interview Magazine singled out Paul as one of the mini gems for excellence in performance in films that year. Benson says, " Paul Hansen Kim, Robin William's assistant in One Hour Photo, so touchingly stalwart as the only person in the glaring, impersonal Sav-Mart to appreciate his boss' fussy perfectionism." Others that Benson acknowledged in the article along with Paul are actors Viola Davis, Billy Connolly and Chavela Vargas. Paul is thankful to Mark, and casting directors Deborah Aquila and Tricia Wood for giving him the opportunity of a lifetime.

Since then, Paul has continued to work on films and television that include The Hulk, a recurring role on ER, the Dorm Daze series, The Pretender, and many others. His most recent credits include the upcoming Ryan Murphy series American Crime Story playing forensics expert Dr. Henry Lee, Message From the King starring Chadwick Boseman, and Jane the Virgin.