La Viola, who went down 2-1 at Bologna on Tuesday, started on the front foot and took an early lead through Manuel Pasqual's fine free-kick.
Chievo substitute Isaac Cofie got the visitors back on level terms seven minutes before half-time, but Larrondo - a 65th-minute replacement for Stevan Jovetic - had the last word with the decisive goal 12 minutes from time.
The result lifted sixth-placed Fiorentina back within three points of third-spotted AC Milan, who defeated Lazio 3-0 on Saturday night, while the Flying Donkeys remained eight points above the Serie A relegation zone.
The game could hardly have got off to a better start for the hosts, as Pasqual despatched a superb curling free-kick into the top-right corner in the fourth minute with visiting goalkeeper Christian Puggioni well beaten.
Cyril Thereau should have equalised seven minutes later but headed wide from Nicolas Frey's right-wing cross.
The home team mustered a couple of opportunities to double their lead, Borja Valero failing to capitalise on good work by Adem Ljajic and Jovetic and then Jovetic heading inches wide from Valero's centre, but when the next goal arrived it fell to the visitors.
Roberto Guana provided the assist from the right and Cofie made no mistake in the middle, slotting into the bottom-right corner.
Luca Toni could have restored Fiorentina's lead before the break but nodded Valero's corner narrowly wide at the near post.
Puggioni was called upon to keep Chievo on level terms three minutes into the second period, getting down well to keep out substitute Romulo's long-range blast.
Valero was just off target with a couple of efforts and also set up Toni, whose header struck the post, with Larrondo contriving to miss the target from the follow-up.
A second Fiorentina goal was looking on the cards, and it arrived in the 78th minute. Pasqual's free-kick from the right found Toni, whose header was nodded home from close range by Larrondo.