With an entertaining contest heading into injury time Le Fondre chanced his arm with a curling shot from 25 yards out and his ambition came up trumps as his strike found the corner of City net.
Bradford made a lively start with Chilean striker Willy Topp impressing, but a howler by centre-half Matt Clarke after 11 minutes gifted the opener to the visitors.
There seemed little danger when David Perkins pushed the ball into the City box, but the luckless centre-half watched in horror as his attempted back pass wrong-footed keeper Scott Loach and rolled into the empty net.
Four minutes later City's luck was out again when winger Omar Daley saw his fierce drive hit defender Marcus Holness and fly inches wide of the Rochdale net.
Bantams' midfielder Lee Bullock fired wide with a 12-yard volley, but another defensive lapse almost cost the home side dear.
Striker Rene Howe pounced on another loose ball to round keeper Loach, but as he tried to lay on a chance for Lee Thorpe, Clarke got back to scramble the ball away.
The visitors stepped up a gear and skipper Gary Jones almost grabbed a second, but some more last-ditch defending snuffed out the danger.
Former Bradford player Ben Muirhead then raced 60 metres before picking out Thorpe, but as Loach raced out the striker could only lift his shot wide of the mark.
Six minutes before the break Jones wasted another great chance when he failed to hit the target after bursting on to Howe's pass and in the dying seconds of the half City struck back.
Midfielder Eddie Johnson chanced his arm with a long-range strike and when the ball deflected kindly into the path of City's top scorer Peter Thorne, he coolly drilled his shot under James Spencer.
Loach made up for his part in the Rochdale opener with a stunning save at the start of the second period to deny the dangerous Howe and both sides went close as the chances came thick and fast.
Thorne almost grabbed a second with two long-range strikes and Clarke pulled off a vital block to deny Muirhead a goal on his return to Valley Parade.
But with the game seemingly heading for a draw Le Fondre had one last trick up his sleeve and Loach had no chance as a well-struck shot flew into the net to send the visiting fans home happy.