Rinse potatoes thoroughly and cut into 2- to 3-inch chunks. Place into a large pot and cover with just enough hot water to be about 1 inch over the top of the potatoes. Bring to a boil.
Boil until potatoes slide off the end of a fork when poked, 15 to 20 minutes. Drain in a colander and return to the pot.
Mix in cream cheese, butter, garlic, and salt. Use a potato masher to mash the potatoes, then stir with a wooden spoon to mix thoroughly.