Leo belongs to the element of Fire and moves through life in the Fixed mode, ruled by Sun. Capricorn belongs to the element of Earth and moves in the Cardinal mode, ruled by Saturn.
Fire wants to move fast; earth wants to move surely. This is the most common source of friction in fire–earth pairings, and it is also where the growth lives. One partner teaches momentum, the other teaches patience.
One of you starts, the other builds. This is a productive mix — the cardinal partner launches, the fixed partner sees it through. Resentment only creeps in when the fixed partner feels rushed.
One sign is active, the other receptive — the classic complementary polarity that most astrological literature treats as a natural fit. One of you leads the outward motion, the other holds the inner world.
What follows is a general read on this pair. Real compatibility depends on the whole natal chart — use the calculator linked on this page to compare two full charts when you're ready.