Attach the pineapple slices to the ham with toothpicks. Space them out for consistent smoking contact. Reserve the juice for the glaze.
Place the pineapple-covered ham large cut side down on the bottom rack of the smoker. Use a cookie sheet placed below to catch juices.
To prepare the glaze, combine ½ cup pineapple juice, brown sugar, and pineapple preserves in a medium saucepan.
Stir to combine and simmer on low to dissolve the sugar. The glaze will become fluid and transparent.
Once the internal ham temperature reaches 110 F, after 3 to 4 hours of smoking time, start glazing the ham. Continue glazing every 15 minutes until the internal ham temperature reaches 140 F, about 1 hour.