Preheat the oven to 350°F. Grease and lightly flour a 9-inch loaf pan.
Cream together the softened butter and brown sugar in a large mixing bowl until smooth and well combined.
Add the eggs and vanilla extract, stirring until just incorporated.
Mix in the grated zucchini and crushed pineapple (with juice) until evenly distributed throughout the batter.
Combine the dry ingredients—flour, baking soda, cinnamon, and salt in a separate bowl.
Add the dry ingredients to the wet mixture. Stir until just combined; the batter should be thick and slightly wet.
Pour the batter into the prepared loaf pan and spread evenly.
Bake for 50 to 60 minutes, or until a toothpick inserted in the center comes out clean.
Cool the bread in the pan for about 10 minutes, then carefully transfer it to a wire rack to cool completely.