The 26-year old South Korea captain has agreed personal terms with the Gunners after completing a medical with the deal being confirmed by Arsene Wenger.
"We are delighted to have signed Chu. He will add true quality to our attacking forces and will be a valuable addition to the squad,” the under-fire Frenchman said.
Park, who was set to join Lille before the Gunners swooped, said he is excited about the next phase in his football career.
"In my opinion this is a great club, now I have to show what I can do on the pitch. I will do my best, I will never give up, I will show heart, I will give everything and I hope [the fans] will support me."