The 60-year-old US actor appeared in court charged with punching the man on 2 November during the dispute in front of his Manhattan apartment. He agreed to take an anger management class and pay a $120 (£91) fine.
Baldwin, who portrays President Donald Trump on Saturday Night Live, has been arrested for disorderly conduct before.
He initially faced a misdemeanor assault charge in this most recent case, though his lawyer said there was video evidence proving the actor had not punched the other driver, who US media have identified as 49-year-old Wojciech Cieszkowski.
As a part of Wednesday’s guilty plea, Baldwin will need to complete the anger management programme by 22 March, his next court date.