Claypool, 53, is a longtime ally of Emanuel who served on his transportation transition committee ahead of Emanuel's May 16 swearing-in. The two worked as political operatives on a Downstate congressional campaign when both were still in college.
Claypool later became a partner with David Axelrod, now a close political confidante of President Barack Obama, in a political consulting firm. In the late 1980s, Claypool become Daley’s chief of staff, a position he held twice.
Daley also appointed Claypool as superintendent of the Chicago Park District in the mid-1990s, where he was credited for reducing costs and expanding programs.
At the county board Claypool challenged the Daley-backed administration of the late President John Stroger and became a leading critic of his son, former board President Todd Stroger. Claypool quit the county board last year to mount an independent bid for Cook County assessor but lost to Joe Berrios, chairman of the Cook County Democratic Party.