The City head coach, who was removed as Forest manager on Boxing Day with the side on the cusp of the play-off places, masterminded a vital three points at Ashton Gate in his new club's battle for survival.
Steven Davies opened the scoring five minutes after the break before long-serving midfielder Marvin Elliott, back from international duty with Jamaica, nodded home the second 12 minutes later to secure City's third successive home win.
Forest, managed by caretaker boss Rob Kelly ahead of Billy Davies' first day back in charge on Monday, were made to pay for a big miss by Dexter Blackstock in the first half as they sunk to defeat.
O'Driscoll, whose squad trained on Saturday morning due to the number of injuries and players returning from international duty, handed Jon Stead a start up front in the absence of Sam Baldock and the former Blackburn striker forced Karl Darlow into a save with a low 25-yard shot after a smart turn in the early exchanges.
Adlene Guedioura was one of three changes made by Kelly and he was next to try his luck from distance but the midfielder failed to test Tom Heaton.
But the visitors should really have taken the lead in the 22nd minute when Blackstock, back in the Forest starting line-up, somehow rattled the woodwork from two yards out after a inch-perfect delivery from Andy Reid.
At the other end Greg Cunningham, who scored the first goal of his club career in City's last outing at Ashton Gate, got away a shot which Darlow pushed wide.
City were enjoying plenty of possession as the game reached the half hour stage with Davies next to try his luck with a curling 25-yard free-kick which flew just wide.
Winger Paul Anderson has been a regular under O'Driscoll and he really should have opened the scoring against his former club but instead of pulling the trigger when Stead's cross found him six yards out he tried to set up Davies and the Forest defence cleared the danger.
Forest striker Billy Sharp did have the ball in the City net two minutes into the second half but the whistle had already gone for offside against the former Southampton man.
And just three minutes later the home side opened the scoring when Davies span and fired a low left-footed shot into the bottom corner for his 10th goal of the season and a potentially crucial one in the battle for survival.
But they had keeper Heaton to thank for a vital stop with his feet to keep out Sharp's right-foot shot from the centre of the box eight minutes later.
And that save looked even more crucial in the 62nd minute when Stephen Pearson's free-kick from the wing found the head of Elliott five yards out to send Ashton Gate into raptures on his 200th start for the Robins.
Kelly introduced Lewis McGugan as the game began to slip away from the visitors and he had the next chance but he blazed over the bar when well placed.