The old record was a $1 million deal former USC running back Reggie Bush got in 2006 with adidas. The actual terms of Newton's deal were not released.
Under Amour will have a collection of Newton Auburn items that includes jerseys with his name on the back (a no-no if he were still in college), football training gear and a signature shoe line.
Auburn has been sponsored by Under Armour since 2005.
Newton, who left Auburn after his junior year, is expected to go in the first half of the first round in April's NFL draft.