As columnist for the Scripps Howard News Service, Mattingly has written "On Religion", a nationally syndicated column, since the summer of 1988.

Mattingly was also Director of The Washington Journalism Center,[1] a program run by the Council for Christian Colleges and Universities.

As the current director of the Washington Journalism Center, Mattingly teaches journalism to students in Washington, D.C. Mattingly has a long association with Howard Ahmanson Jr. and his wife, Roberta, dating back to Roberta's tenure as a religion reporter for The Orange County Register in the late 1980s.

Roberta was an original financial backer of GetReligion and Ahmanson has funded the Washington Journalism Center and the Oxford Centre for Religion and Public Life, which currently hosts the website.

[2] After leaving the Southern Baptist Convention, the Christian body in which he was raised, Mattingly was for a time a member of Episcopal Church.