He graduated from Cascade High School in Cascade, Iowa. Craig attended college at the University of North Carolina Wilmington where he played on the men"s basketball team
Early life and education
In 2011 he has got the Italian passport as naturalized. He played at the University of North Carolina Wilmington from 1999-2003. Callahan gained notoriety during his time at UNCW as he helped lead the team into 3 National Collegiate Athletic Association Tournaments (1999, 2002, 2003).During his senior year with the Seahawks, he averaged over 16 points and 6 rebounds a game.
After graduating from college with a Finance Degree, he played professional basketball in the Czechoslovakian Republic from 2003–2006, and was named Most Valuable Player of the NBL in 2006.
Due to their success in 2007, Ricoh Manresa. gained entry back into the Liga ACB in 2008. In November 2008, Callahan was signed by the Eisbaren Bremerhaven (the Bremerhaven Polar Bears) of Germany"s top league.
A vital addition to the team, Callahan was one of the league"s top scorers averaging over 17 points, and 6.9 rebounds a game. During the summer of 2011 he singned a contract with New Basket Brindisi, basketball team which play the second Italian national league.
Next season he played with Sigma Barcellona.
In August 2013, he signed with Tezenis Verona. In July 2014, he signed a one-year deal with Pallacanestro Varese. During the off-season he resides in Jacksonville, Florida.