Bundled out of Europe by Ajax in midweek, Massimiliano Allegri's men completed a domestic formality thanks to Alex Sandro's first-half header and a German Pezzella own goal eight minutes after the interval.
One point stood between Juve and an eighth-successive Scudetto and they were made to work for all three following Nikola Milenkovic's surprise sixth-minute opener.
The woodwork twice prevented Federico Chiesa from making life more difficult for the Bianconeri, but they shook off the lethargy in the second half to open an insurmountable lead over second-place Napoli.
Juve's confidence, diminished after their loss to Ajax, ebbed further when Chiesa's cross broke perfectly for midfielder Milenkovic to sweep home.
Fiorentina, in contrast, grew in stature, with a combination of the offside flag and the right post denying Giovanni Simeone and winger Chiesa.
The hosts needed inspiration and Alex Sandro provided it with a diving near-post header from Miralem Pjanic's corner in the 37th minute, yet Fiorentina would have surged ahead again had the crossbar not then kept out Chiesa's thumping strike.
The tension was released soon after the interval. Cristiano Ronaldo found space to the right of goal and defender Pezzella turned the attacker's pass into his own net.
Juve were suddenly emboldened by belief and Pjanic, Ronaldo and Juan Cuadrado all saw shots blocked in quick succession.
Their Portuguese superstar ultimately went unrewarded in his attempts to score his 600th club goal, but that can be put on hold as the Bianconeri uncork the champagne.
Allegri worthy of adulation
Allegri was forced to defend his Juve record following the surprise quarter-final exit to Ajax in the Champions League.
While continental success is still clearly the major prize, the ex-AC Milan boss deserves his share of plaudits for juggling egos and orchestrating the most serene of title triumphs, his sixth overall in Serie A.
