City News Service reports 52-year-old John Haw performed legal and construction consulting services while the Pasadena hospital was expanding its emergency department.
Under two contracts with the hospital, Haw was paid nearly $350,000 from March 2008 through April 2009.
Prosecutors say Haw also had an agreement with David Hamedany, Huntington's ex-director of construction, under which Haw paid kickbacks in exchange for promises of more work.
Haw is set to be sentenced Feb. 4.
Hamedany was sentenced in January to three years in federal prison and ordered to pay $4.8 million in restitution.