The Cardiff manager had come under fire for failing to deliver a promotion challenge with the Welsh club this season - but the former Notts County manager enjoyed his return to his hometown, as first half goals from Joe Ralls and Eoin Doyle put his side in control.
Dexter Blackstock did pull one back in injury time, following the 76th minute dismissal of keeper David Marshall for an apparent head-butt on Jamaal Lascelles.
But it was Freedman who was to end the afternoon frustrated, after seeing the Reds notch up a fourth consecutive home defeat, amid a limp finish to the campaign.
Forest's frustrating season looked destined for a fitting finale by half time, with Cardiff completely in command. The home fans had hoped to see their side end their run of seven games without a win, but that looked unlikely following an opening 45 minutes that had been dominated by the visitors.
Cardiff took the lead with what was their first real attack in the 14th minute, and took charge from that moment on. The goal came as a cross-shot from Joe Mason took a huge deflection, sending the ball looping to the far post, where Ralls (pictured) was allowed the time and space to apply an emphatic first-time finish, sending a shot high into the roof of the net from six yards.
Forest's response was minimal, with Michail Antonio lashing a shot into the side netting from the edge of the box and Henri Lansbury curling another long range effort high and wide, by only foot or so.
Instead it was Doyle who made it 2-0 in the 24th minute, as Forest's defensive vulnerability was exposed again. Karl Darlow parried a driven, powerful shot from Stuart O'Keefe, but could only direct the ball out to the right flank, where Matthew Kennedy was well placed to fire the ball back into the danger zone. This time it was Doyle given the time and space to apply the finish, heading decisively home, inside the post.
Cardiff might have put the game almost beyond doubt, with Ralls bending a powerful free kick only inches wide of the post from 20-yards, as Forest struggled to get a foothold in the game.
Half time substitute Chuba Akpom almost made an impact with his first touch, forcing a smart save from David Marshall, diving low to his right, with a shot that he failed to properly connect with.
But Forest rarely looked like finding their way back into the game until a moment of madness from Cardiff keeper David Marshall left the visitors down to 10 men.
Marshall was shown a red card by referee Peter Bankes, after he appeared to head-butt Lascelles, right in front of the match official. It left Cardiff a man short for the final 14 minutes.
Substitute keeper Simon Moore made a fine save to deny Blackstock and Ben Turner cleared a Michael Mancienne effort off the line.
Blackstock did manage to pull one back for Forest in the 91st minute, converting a cross from substitute Jamie Paterson at the near post. But Cardiff held out for the win.
Cardiff: Marshall (c), Peltier, Morrison, Turner, Fabio, O'Keefe, Gunnarsson, Ralls, Kennedy (Pilkington 73'), Doyle (Revell 73'), Mason (Moore 78')