Marshall also dished out 13 assists, helping all of the Tar Heels' starters score in double figures. Harrison Barnes chipped in 20 points and John Henson added 14 points and 13 rebounds in UNC's fourth straight win.
North Carolina (24-4, 11-2 ACC) currently holds a half-game lead atop the ACC standings over Duke and Florida State. The Blue Devils and Seminoles square off in Tallahassee on Thursday.
The Wolfpack (18-10, 7-6) have fallen victim to the powerful triumvirate in a six-day span and will look to get back on track against Clemson on Saturday.
They will need a similar effort from C.J. Leslie, who scored 24 points and grabbed 12 rebounds. Lorenzo Brown netted 18 points but shot just 6-of-21 from the field.
The Tar Heels made six of their first 10 three-point attempts, and Marshall's mid-range jumper midway through the first half yielded a 30-19 lead.
NC State responded with the next 11 points to pull even, with Leslie's block of Henson and dunk at the other end sparking the run.
North Carolina withstood the surge and led 46-41 at halftime before quickly pushing it to double digits on a Marshall layup and Barnes three-pointer to begin the second half.
This time, the hosts didn't have an answer, in part because Leslie and Richard Howell were mired in foul trouble. With NC State's starting frontcourt on the bench, the Tar Heels rattled off nine straight points to go on top 71-55.
The closest NC State got over the final eight minutes was 11.
Tyler Zeller and Reggie Bullock both secured eight rebounds to go with 14 and 11 points, respectively, for North Carolina, which will visit Virginia on Saturday...Marshall became just the fourth sophomore in ACC history to reach the 500-assist plateau...NC State shot just 3-of-13 from behind the arc and 13-of-23 from the foul line...Scott Wood scored three points for NC State, 10 below his season average...The Tar Heels swept the season series and have won a school record 12 straight meetings against the Wolfpack.