Martin Olsson's low first-half strike, just reward for a display in which he had David Wheater all at sea, sealed a win which could and should have been more comfortable.
Bolton might have gone in front earlier with Rodrigo Moreno's snap-shot coming back off a post, but they were always second best.
The Bolton fans taunted the hosts with chants of 'You should've kept big Sam' in reference to Steve Kean's predecessor Sam Allardyce, but this was perhaps the Blackburn boss' most important win since taking charge. And, after two straight defeats without scoring, his side were well worth it.
Bolton boss Owen Coyle made four changes to his side following the 3-0 defeat at Fulham in midweek, most notably Hungarian Adam Bogdan coming in for Jussi Jaaskelainen in goal, the veteran Finn dropping to the bench.
But the new faces failed to breathe new life into the visitors, who looked every inch a side with little left to play for this season.
Rovers came into the game just a point above the bottom three, but they started brightly.
Olsson sent in a deep cross from the left which was headed back inside by Brett Emerton and Benjani stabbed the ball wide under pressure from Zat Knight.
Olsson was looking dangerous down the left and he got to the byline, putting in another cross which Brett Emerton, under pressure, hit low straight at Bogdan.
Blackburn almost went in front in the 15th minute when Olsson beat Wheater on his outside in the area to give himself a shooting chance, but his effort was blocked on the line by Paul Robinson before a free-kick allowed Wanderers to clear their lines.
The woodwork came to Blackburn's rescue moments later, though, when Michel Salgado's misdirected header fell to the feet of Moreno, whose snap-shot came back off the near post.
But fittingly it was Olsson who scored the first goal in the 22nd minute to put the hosts ahead. He picked the ball up 25 yards out and, with Wheater backing off, cut inside before toe-poking the ball into the near bottom corner from just outside the area.
Olsson appeared on a one-man mission to save Blackburn from the drop and, after having an effort blocked, saw his follow-up shot turned round the post by Bogdan.
Rovers were dominant now and only a fine sliding tackle from Knight prevented Emerton from breaking into the area.
There was a scare for the hosts when Olsson had to go off after taking a blow to his ankle, but after treatment he was fit to continue.
Emerton had Bogdan worried soon after the restart when, instead of crossing, he went for the near top corner with a free-kick way out on the left, but it dropped just over the bar.
Benjani should have doubled Rovers' lead after the ball fell to him in the six-yard box, but he could not bring it under control and Bogdan smothered.
Salgado was then forced off after hurting himself in a challenge with Gardner and Mame Diouf came on.
Steven Nzonzi almost added to Blackburn's lead when he got to Paul Robinson's long free-kick ahead of Bogdan but his looping header dropped wide.
Mame Diouf, on for Benjani, was guilty of a glaring miss when the ball fell to him 10 yards out and with time to measure his shot, but he miscued it horribly high and wide.
Rovers were opening their opponents up almost at will, though, and the impressive Jermaine Jones sent a cross-shot just wide after a swift break.
Nzonzi then inexplicably headed over when unmarked after Olsson had again skipped past Wheater and crossed as Rovers finished with a flourish.