It's official. Newly appointed Congressional Budget Office (CBO) Director Keith Hall hails from think tank land.
More specifically, he worked at the Mercatus Center at George Mason University, a libertarian think tank in Fairfax, Virginia. The Weekly Standard has called the think tank "relatively low profile."
Here is his Mercatus Center biography, which says he worked at the think tank from April 2012 to September 2014.
Here is a previous Think Tank Watch post on other think tankers who were considered for the CBO post.