From 1970 to 1975 he was on the Border Patrol Police special company fighting the communist insurgency in Thailand.

Following the 2006 coup d'état, Kowit was named third deputy chief of the Council for Democratic Reform under Constitutional Monarchy.

There was speculation about the motivation behind the replacement, as Kowit had earlier arrested several military personnel for alleged involvement in the 2006 Bangkok New Year's Eve bombings.

On 24 September 2008, Kowit was appointed Minister of Interior in Somchai Wongsawat's cabinet, serving until the government broke apart on 2 December 2008.

On 9 August 2011, Kowit was appointed Deputy Prime Minister in Yingluck Shinawatra's cabinet.