England manager Roy Hodgson was forced to hand Spurs sensation Kane his full debut alongside Wayne Rooney due to injuries to both Daniel Sturridge and Danny Welbeck.
But while the 21-year-old Kane failed to shine, Townsend made the most of his 20-minute appearance beating Gianluigi Buffon with a fine strike 11 minutes from full time to level Graziano Pelle’s 29th minute opener.
Hodgson — whose side lost 2-1 to Italy when they met at the group stage in last year’s World Cup finals — admitted the first-half display had been short of what he wanted but he was delighted with the performance following the break.
“I’m really happy with our second half, I thought we were the better team. That’s pleasing in the sense that under (Antonio) Conte, Italy are a strong team,” Hodgson said.
“We’re missing a few players and when they’re available, we have a few more options.”
After what was an “emotional return” for former Juventus handler Antonio Conte, the 45-year-old coach admitted Italy remain a work in progress.
“Today it was prestigious friendly against a side with some top players, but we competed well and I’m happy with our performance,” said Conte.
“Ultimately it was a fair result, because we struggled a little more in the second half.
“But we’re still working to help this squad grow. There are a lot of young players here but thankfully their experiences in their respective leagues has shone through.
“The Italian national shirt means a lot to them and nobody can deny that.”
At the end of an insipid opening half, Italy had most to cheer with Marco Parolo, new Italy recruit Eder and Pelle testing Joe Hart in the England goal prior to the Southampton striker’s headed opener.
Parolo hit a speculative shot from 35 metres that dipped, forcing Hart to react quickly and tip over on 10 minutes.
England’s first real chance came before the half-hour when Kane rose above his marker at the back post. Although his header was blocked, the clearance fell for Rooney to fire a shot which bounced off the bar.
It only served to move Italy up a gear.
Their efforts paid off just before the half hour when Pelle escaped his marker to meet Giorgio Chiellini’s inch-perfect delivery from the left with a glancing header that took Hart totally by surprise before landing inside his far post.
England had the first chance after the restart, when Kane found himself in possession outside the area only to fire his shot straight at Buffon.
But the visitors were immediately on the back foot as Italy pressed.
Pelle did well to set up Italy debutant Mirko Valdifiori and although he beat his marker to set up Eder inside the area, Hart somehow saved from the Sampdoria striker with his legs.
England showed another glimpse when Rooney helped set up Kane to the right of the area, but his deflected shot hit the side netting.
Conte made a triple substitution, Ignazio Abate replacing Florenzi, Franco Vazquez replacing Eder to make his Italy debut and Pelle making way for Ciro Immobile.
Immobile was robbed of a great chance in front of goal seconds later, and at the other end Rooney spurned a great chance when he fired straight at an alert Buffon when Kieran Gibbs’ long cross caught Chiellini unawares.
Rooney came close again, his slight touch in front of goal from Kane’s drive trickling just wide of Buffon’s far post.
England’s pressure finally paid off with Townsend, who replaced Fabian Delph on 70 minutes, creating space on the edge of the area to beat Buffon with a precise shot at the keeper’s far post.
Italy were let off the hook moments later when Rooney ran down unchallenged on the left only to see his low drive blocked by Buffon.
Italy pressed for a late winner but Vazquez saw his shot flash just wide of Hart’s far post after a move which saw the Palermo striker run on to Immobile’s ball.