The president-elect made a similar pledge on social media in early December. His latest comments came during a wide-ranging news conference from Mar-a-Lago.
A judge threw out a suit against Fox News by a former Trump supporter who said he got death threats when the network aired false conspiracy theories about his involvement in the Jan. 6 insurrection.
The move was widely expected after Trump's election victory, and is in line with longstanding Justice Department policy that says a sitting president cannot be indicted or tried on criminal charges.