Carroll, reported to be at the centre of a alleged training ground incident which left team-mate Steven Taylor nursing a broken jaw, rifled home a second-half winner to keep his boyhood team on course for an instant return to the top flight.
Newcastle's preparations had been overshadowed by the incident and, amid speculation that furious owner Mike Ashley had launched an internal investigation, St James' Park insiders feared the bust-up could undermine the Magpies' title run-in.
Taylor, 24, out since January with a knee injury, has been discharged from Newcastle General Hospital, where he had been admitted over the weekend.
Carroll, whose 16th goal of the season eclipsed another impressive showing by Sean O'Driscoll's Doncaster, also faces a Crown Court appearance next month on an assault charge in connection with an incident at a city night-spot last December.
But the bustling centre-forward justified Chris Hughton's decision to include him in the starting line-up with another outstanding on-field contribution.
Nicky Butt returned as Newcastle skipper and Tamas Kadar was also recalled by the Magpies.
Doncaster's leading goalscorer Billy Sharp and Dean Shiels returned for the home side.
Carroll, wearing gloves, was off target with an early snapshot and soon after just failed to make proper contact with Ryan Taylor's corner.
But it was Newcastle goalkeeper Stephen Harper who was forced to make the first significant save in the 21st minute, brilliantly keeping out Sharp's low shot from 10 yards, one-handed, before Danny Simpson hacked the ball clear.
Sharp should have scored in the 30th minute. Shiels and James Hayter combined down the right and from the latter's ball across the box, the Rovers striker shot straight at Harper from six yards.
Carroll, set free by Wayne Routledge, then galloped into the left edge of the Doncaster penalty area and forced home goalkeeper Neil Sullivan into a flying save with a venomous drive.
Newcastle midfielder Nolan was booked for failing to retreat from a corner late in the first half and Simpson followed him into Hertfordshire referee Keith Hill's notebook early in the second.
Doncaster probed patiently after the restart, but Newcastle broke with menace and took the lead with a rapier counter-attack in the 59th minute.
Routledge slipped the ball down the right channel into Carroll's path and the big forward motored on to the ball, held off Gareth Roberts' desperate challenge and kept his composure to fire home a right-footed shot past Sullivan.
Rovers were denied an instant riposte by the assistant's flag when Sharp lashed home a rebound, while another devastating burst into the Rovers' area from Carroll almost resulted in the visitors' second, but his inviting ball across the face of goal evaded everybody.
Jay Emmanuel-Thomas replaced Doncaster midfielder Mark Wilson in the 74th minute and, to a chorus of boos from the home fans, Newcastle's Joey Barton came on for Guthrie, for his first appearance since September when he broke a bone in his right foot.
Rovers pair John Spicer and Jordan Mutch were sent on by O'Driscoll for Shiels and Roberts in the closing stages, but the visitors withstood late Rovers pressure to extend their unbeaten league run to nine matches.