Day 1 Richard Walsh Richard was a founding father of CTU. He was shot by Ira after retrieving a key card from Scott.
Ryan Chappelle Ryan worked at Division during Day 1. He was next in line for director after Richard.
Day 2 Ryan Chappelle
Brad Hammond Brad took over after Ryan's disappearance.
Ryan Chappelle
Day 3 Ryan Chappelle Ryan was in this position when President Palmer asked him to sacrifice himself by order of Stephen, a terrorist who had 11 vials of Cordilla Virus and threatened to release it if President Palmer didn't cooperate. Ryan was hesitant at first, but realized it was for the country and gave himself up. He was shot in the head and died.
Brad Hammond Brad took over again and also took over CTU Los Angeles temporarily.
Day 4 Bill Buchanan Bill took over as Director. He oversaw the progress by Michelle and CTU Los Angeles during Day 4.
Day 5 Bill Buchanan After Michelle resigned, he had no choice but to put himself in charge of CTU Los Angeles, making him in charge of Division and CTU Los Angeles.
Day 6 Bill Buchanan
Bill was still in both positions until Karen had to fire him for political reasons.
Day 7 Vacant After Bill was fired, Division had no one else in line to become Director. They will probably reveal a new director in Day 7, though according to John Cassar and Evan we will see little if not any of CTU in Day 7.