Commons (3) struck when he collected a pass from Virgil van Dijk and played a one-two with Georgios Samaras before blasting a shot through the legs of Dean Brill from the left side of the box.
Celtic almost doubled their lead when Tony Stokes crashed his shot across the face of goal after Emilio Izaguirre's delivery into the box dropped at the back post off the head of Nick Draper.
Seconds later Caley Thistle could have levelled when a crisp delivery from Aaron Doran found Billy McKay but the striker's header lacked the power to beat the diving Fraser Forster.
Inverness came close again when Marley Watkins nicked the ball off Joe Ledley on the Celtic bye-line and laid the ball back to Graeme Shinnie, whose powerful drive was blocked by Forster at his near post.
Caley Thistle continued to show why they have been among the leading pack all season as Forster was forced to turn another drive from Shinnie wide for a corner just after the break.
But Commons was inches away from adding his second on the hour when he flicked the ball inches past the target from a low Stokes cross following an exchange of passes at the corner of the box.
Two minutes later Commons took a pass from James Forrest and his chip came off the crossbar and the Celtic scorer was denied again when Brill saved his shot from 12 yards after Samaras and Stokes combined to set up the chance.
Forster tipped over a looping header from Gary Warren and Scott Brown shot straight at Brill at the other end in the dying minutes after Stokes had created the chance.
Inverness substitute Ryan Christie was wrongly flagged offside a minute later as he headed wide with the goal as his mercy, but Celtic stood firm to earn a seventh successive Scottish Premiership win.