Smith's successful stint during the regular season earned him a spot on the Rockies' 2007 postseason roster. In the 2007 National League Division Series against the Philadelphia Phillies, Smith had one pinch hit in two at bats. His lone hit came in the second game of the series in a 10–5 win against the Phillies. It was an infield hit in the top of the fourth inning that loaded the bases with the Rockies down, 3–2. The next batter, Colorado second baseman Kazuo Matsui, went on to hit a memorable grand slam to give the Rockies a lead that they would never relinquish. Colorado went on to sweep the Phillies in three games and then went on to sweep the Arizona Diamondbacks in four games in the 2007 National League Championship Series. Once again, Smith had one pinch hit in two at bats. The one hit was in the fourth game of the series in a 6–4 series-clinching win against the Diamondbacks. This time, Smith hit a double that came with two outs and two runners in scoring position in the bottom of the fourth inning with the Rockies down, 1–0. The double drove in both runners to give Colorado a 2–1 lead. Smith then went on to score during the inning after a Matsui single. Colorado left fielder Matt Holliday also hit a three-run home run in the fourth inning to cap off a six-run fourth inning, all with two outs.