Spurred into action by the September 11, 2001 attacks in the United States - in which most of the militants involved were Saudi nationals - and radical Islamist bombings in Saudi Arabia two years later, the king has brought together Sunni and Shi'ite Muslims in Mecca to discuss how to counter extremism in Islam.
He hosted an interfaith conference in 2008 but had to hold it in Madrid because the kingdom is so conservative. However, Saudi officials at the Vienna conference stressed the dialogue message was being spread back home as well.
"The aim is to promote acceptance of other cultures, moderation and tolerance," said Fahad Sultan AlSultan, deputy head of a Saudi national dialogue effort launched in 2003. "There are problems but we have achieved some success."
KAICIID is managed by a board with three Muslims, three Christians, a Jew, a Buddhist and a Hindu. It aims to help religions contribute to solving problems such as conflicts, prejudice and health crises rather than be misused to worsen them.
"The prime purpose is to empower the active work of those in the field, whether in the field of dialogue, of social activism or of conflict resolution," said Jerusalem-based Rabbi David Rosen, representing Judaism on the nine-seat board of directors.
Unlike other interfaith projects run by churches or non-governmental organizations, KAICIID is an international body sponsored by Saudi Arabia, Austria and Spain, with strong backing from the Vatican as a "founding observer".