The former Chuck star will play Captain Steven Harris on the show, according to TV Guide.
His character will serve as the squad's new captain, in the wake of Dann Florek's character Captain Donald Cragen's murder charges from the show's season finale.
Baldwin will reportedly make his debut on the show in the upcoming season's first three episodes.
Best known for his work on Chuck and Firefly, Baldwin most recently guest starred on Leverage.
Law & Order: SVU returns for a two-hour premiere on September 26 on NBC.