The Tottenham winger scored his 10th goal for his country with a smart finish as he made full use of Joe Allen's lovely lofted pass in the 21st minute.
The hosts had to survive some nervy moments, notably when Emanuel Pogatetz had a header wrongly ruled out for offside and David Alaba struck the post, but Bale made another telling contribution with a pin-point cross for substitute Sam Vokes to head in the second early in the second half.
Captain Marc Janko pulled a goal back for Austria but Wales held on for a valuable win.
Manager Chris Coleman has endured a difficult first year in charge, claiming just one win from seven games, but he will have been pleased to see his side finally play with a fluidity that had been sorely lacking, and restore some confidence ahead of next month's World Cup qualifiers against Scotland and Croatia.
For that, the former Fulham boss will be grateful to Bale, who has now scored seven goals in his last nine internationals, and he tormented the Austrian defence with his trademark power and pace before being withdrawn on the hour mark.
After a disappointing start to their World Cup qualifying campaign, Wales were able to field Craig Bellamy and Bale in the same side for the first time in a year, even though former captain Aaron Ramsey was absent with a calf problem.
Wales had to survive an early scare as Adam Matthews was forced to clear an attempted defensive block off his own line
But the visitors' fear of Bale's speed was clear to see from the moment he first got on the ball, as he took off on a thrilling 70-yard dash beyond Markus Suttner and Pogatetz, but his cross fell behind Jack Collison.
Bellamy, playing for Wales for the first time since August, almost marked his return with a goal as David Vaughan played him in with a sharp first time pass, but the striker's shot ran agonisingly wide of the far post.
Bale, however, made no such mistake when he was picked out by a Allen's perfectly judged pass, cutting inside to slot low beyond Robert Almer.
Austria responded strongly to falling behind and Wales had to withstand concerted pressure to retain the lead.
Pogatetz bundled home after Janko had headed Andreas Ivanschitz's free-kick across the box, but the assistant referee had his flag raised for offside, although replays showed it was the wrong decision.
And the excellent Alaba almost equalised right on half-time with a stunning volley. Allen's weak header fell to the midfielder and his superb strike beat Boaz Myhill only to hit the base of the post.
Coleman made two changes at the break, bringing on Vokes and Andy King for Bellamy and Vaughan respectively.
And Vokes made an almost instant impact as he doubled the home side's lead seven minutes into the second half.
Ben Davies seized on Alaba's loose pass and switched play to Bale, whose fierce centre saw the Burnley striker get ahead of his marker to power home a header.
Bale should have made it 3-0 just two minutes later after Collison's half-cleared cross fell to him, but he put his volley just wide.
That was the winger's last meaningful contribution as he was withdrawn on the hour for Hal Robson-Kanu.
Wales looked less assured without their talisman, and the visitors set-up a tense finale by pulling a goal back with quarter of an hour to play.
Marko Arnautovic floated in a deep cross and Janko had the easy task of heading high past Myhill.
Werder Bremen midfielder Arnautovic then curled an effort just wide as Wales dropped deep, but the hosts held out.