Brennan began his CIA career as an analyst and spent 25 years with the agency . He was a daily intelligence briefer for President Bill Clinton . In 1996 , he was CIA station chief in Riyadh , Saudi Arabia , when the Khobar Towers bombing killed 19 U.S. servicemen . In 1999 , he was appointed chief of staff to George Tenet , then-Director of the CIA . Brennan became deputy executive director of the CIA in March 2001 . He was director of the newly created Terrorist Threat Integration Center from 2003 to 2004 , an office that sifted through and compiled information for President Bush 's daily top secret intelligence briefings and employed the services of analysts from a dozen U.S. agencies and entities
Khobar Towers bombing
Khobar Towers bombing
John O. Brennan