The Viola opened their Serie A campaign with a home win thanks to two goals in the first half in what was a lively match, the Italy striker's opener his first goal in 15 months
First-half goals from Giuseppe Rossi and David Pizarro sandwiched Pablo Barrientos's effort to hand Vincenzo Montella's side a morale-boosting victory.
Rossi opened the scoring in the 14th minute when he placed home from eight yards after meeting Juan Cuadrado's cutback but Sebastian Leto then came close to an equaliser when his header was saved by Norberto Neto.
And Catania did draw level in the 22nd minute when Barrientos found the bottom corner with a left-footed strike from inside the area.
The visitors were unable to build on that momentum, however, and Fiorentina were back in front just six minutes later. Pizarro worked his way to the right hand side of the box before unleashing a fierce drive that found the top corner.
The result means that the Viola have now won 12 and drawn five of the 17 home top-flight matches that they have played against Catania.
Montella's men sit in sixth position after the opening weekend of fixtures in Serie A and continue their season with a trip to Genoa on Sunday, while Catania will look for their first points when they host Inter.