The FBI said 13 defendants have been taken into custody in the Los Angeles area, including Huffman.
Court papers said a co-operating witness met Huffman and her husband, actor William H Macy, at their Los Angeles home and explained the scam to them.
That message earned attention after it was revealed Huffman was among those charged as part of the alleged scheme.
The racketeering conspiracy charges were brought against coaches at schools including Wake Forest, Stanford, Georgetown, the University of Southern California and University of California, Los Angeles.