Tom Thibodeau officially became coach of the Bulls on Wednesday. (AP)

On Wednesday, the Chicago Bulls announced Tom Thibodeau as their new head coach.

“I am very excited to be here and to join the Bulls organization. Chicago is a great city with great fans and a storied history,” Thibodeau said. “I would like to thank Jerry Reinsdorf and [general manager] Gar Forman for presenting me with such a terrific opportunity. We have a talented team with a good nucleus of players, and I am eager to get started.”

Thibodeau served as an assistant coach for the Celtics from 2007-10. He had been drawing interest for head coaching positions since helping lead the C’s to the 2008 championship as an assistant coach. The Celtics repeatedly have credited his emphasis on defense as a key to their success.

“I am extremely pleased to welcome Tom Thibodeau as our new head coach,” Forman said. “As I went through the process to search for the next head coach of the Chicago Bulls, the longer the process went it became apparent that Tom was a perfect fit for the Bulls. He is a great communicator and teacher of the game, and he fits our organizational philosophy from a defensive standpoint. With his experience and knowledge of the NBA, I am confident he will be a great leader for our team.”

The Celtics will look to replace Thibodeau on the sideline this summer.