Finally figured it out. It's sort of weird, but this is what I had to do:
<LinearLayout
android:id="@+id/everything_but_description"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_weight="1"
android:orientation="horizontal" />
<TextView
android:id="@+id/description"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="@string/paragraph" />
I had to have both set to "wrap_content" but give the one I wanted to fill the remaining space a weight WITHOUT giving the other one a weight. Very weird workaround but it works perfectly.