The tough center back has joined Milan on a free Bosman transfer from his former club, Standard Liege. He was out of contract and was linked previously with Ajax.
This is the biggest move by a US player in the international arena. The news has created ripples. Here is Bob Bradley.
"It's very exciting," Bradley said of the news of Onyewu's transfer. "(Milan is) one of the great clubs in the world. Certainly, the experience that he'll get there will really be important as we move forward with our national team."