The Gunners star was snapped on holiday in Las Vegas smoking a cigarette at a pool party with England teammate Joe Hart.
Former Arsenal manager George Graham condemned the England international, but R's boss Redknapp believes that smoking does not necessarily mean elite players are affecting their ability to perform to their highest level.
Speaking to talkSPORT, the former Spurs manager said: “Over the years a lot of foreign players that I've managed, and I mean top players, have smoked.
“I’m not condoning it or encouraging it, but an awful lot of foreign players did smoke. Johan Cruyff apparently when he was in his prime, was a big smoker.
“Certainly, the Croatian boys, Slaven Bilic and all the lads, at every opportunity they had a cigarette. It is not good for him, that is for sure, and Arsene Wenger wasn’t happy last time he was caught smoking in the early hours at a nightclub, but he is a young player.”
However, Redknapp did concede that Wilshere has not hit the heights expected of him when he first burst onto the scene with Arsenal.
“He hasn’t really moved on to the level where we thought he would now be the main man for Arsenal and England," he added.
“He has got to hopefully stay fit this year. He has got to have a big year and start fulfilling that fantastic potential he showed as a young player."
Arsenal begin their new campaign against Crystal Palace next month.