Smith made 13 of his saves in the third period in notching his first shutout of the season and 11th of his career. He is now 12-6-1 for the playoff-bound Lightning.
Lecavalier, stationed to the left of the crease, tapped in a quick pass from Martin St. Louis 7:56 into the first period to give Tampa Bay all the scoring it would need.
Lecavalier, however, left the game in the second period after being hit with a high stick and didn't return.
Nate Thompson added an empty-netter for Bolts, who assured themselves no worse than a fifth seed in the Eastern Conference playoffs with the victory.
Corey Crawford made only 13 saves for Chicago, which came into the game with a three-point cushion for the eighth and final Western Conference playoff spot.