Australian international Cahill had not found the net on the top-flight stage since scoring against Manchester City in December 2010.
But he ended his long drought from close range in the 24th minute amid controversy after Marouane Fellaini clearly handled in the build-up to the goal.
Yet Cahill's joy was short lived as David Goodwillie netted a 74th minute equaliser after the Everton player had fired into the Blackburn striker's stomach before seeing the ball ricochet over the line.
Rovers have spent most of the season in the bottom three but they thoroughly deserved a priceless point even though Everton defender Shane Duffy headed against the bar in the closing stages.
With former Everton striker Yakubu suspended, Blackburn signed Anthony Modeste on loan from Bordeaux two days before the game but there was no room for the French striker in the side.
Modeste had to make do with a place on the substitutes bench as Kean started with Goodwillie as Rovers looked to build on their recent encouraging form which included wins over Fulham and Manchester United in the last three league games.
Rovers were missing Chris Samba after the want-away Congolese defender handed in a transfer request yet, despite his absence, Blackburn did everything but score before half-time.
After Scott Dann had a header cleared off the line, midfielder David Dunn hit the post with a low curling effort following a sweeping 37th minute move involving Goodwillie and Dunn.
Everton keeper Tim Howard was also forced to save with his foot to deny the busy Dunn a certain goal yet despite the controversy in the build-up to Cahill's goal, Blackburn were once again let down by their defensive failings.
Kean's side have not kept a clean sheet in the Premier League since April 30 last year.
Keeper Paul Robinson chased referee Mark Halsey out of his area after Cahill stabbed home from close range claiming Fellaini had handled just before the former Millwall player scored.
He had a point but Cahill was still afforded too much time and space to end his long run without a goal.
Everton have struggled for goals all season but it was the kind of fortune that has been missing from their campaign.
Victor Anichebe should have broken the deadlock as early as the third minute but hit his volley into the ground allowing the ball to bounce over the bar while United States international Landon Donovan blazed over after bursting into the Blackburn area.
While the game remained 1-0, Blackburn had a chance of salvaging a point.
Junior Hoilett was a constant threat for the visitors yet Blackburn looked to be heading for defeat.
Howard was able to save comfortably from Jason Lowe's deflected cross while substitute Mauro Formica spurned another chance when he fired wide from 20-yards.
But Everton were stunned when Goodwillie found the net 16 minutes from time.
Morten Gamst Pedersen's free-kick somehow eluded Howard but Cahill appeared to clear the danger when he stopped the ball crossing the line. But he only succeeded in firing the ball into Goodwillie who was able to equalise.
There was still time for Duffy to head against the bar.
And in the dying moments Formica went close to a Blackburn winner before Fellaini had an effort cleared off the line after being frustrated by a fine Robinson save as Everton finished strongly.
Source: AFP
Source: AFP