Aries rising, the person who walks in first
Aries rising means Aries was the sign coming up over the eastern horizon at the moment you were born, and it sets how you meet the world: fast and direct, already reaching for the door handle. People take you for someone who has already decided, even on the days you haven't.
Your rising sign, or ascendant, is the manner you lead with: the first impression, the way you begin things, the pace you move at before anyone knows you well. Working it out needs an accurate birth time and place, because the sign on the horizon changes about every two hours on average. If you're not sure of yours, start with the rising sign guide.
The first one through the door
With Aries rising you start before the plan is finished. In a group you're the one who says "let's just try it", and you mean right now. You walk quickly, you answer the question before the other person reaches the end of it, and whatever you feel shows on your face a second later. People find you easy to read, which is its own kind of honesty.
Traditional astrology links this rising sign with the head and face: a strong brow, a quick stride, a habit of leading with the forehead when you walk. Treat those as old associations, not a description you have to match. What people actually notice first is the speed.
The cost is that speed reads as temper. You say "no, that won't work" in the same breath you thought it, and someone across the table hears a door slam. You also start more than you finish, because the opening of anything is where you feel most awake.
Mars, your chart ruler
Aries is ruled by Mars, which makes Mars your chart ruler, and its position matters a lot. It shows where all that starting energy actually goes. Mars in the 10th house puts it into work and reputation. Mars in Cancer turns the edge protective, so you're quickest to fight for family. Mars in Libra, the sign opposite your rising, sets up a running argument between charging ahead and keeping the peace: people meet the charge first and the diplomat later.
When the inside runs at a different speed
The rising sign is the front, not the whole person. If your Sun is in a slow sign like Taurus or Capricorn, people expect a sprinter and get someone who thinks for a week before committing, and they're thrown by it. With a Moon in Pisces or Cancer, the brisk front covers feelings that take far longer to settle than your face suggests.
If your Sun or Moon is also in Aries, the front and the inside match, and the whole chart moves at one pace. Compare Sun in Aries, which is about what drives you, and Moon in Aries, which is how you react when something lands.
How common it is
In the Northern Hemisphere Aries is a sign of short ascension: it clears the horizon quickly, sometimes in under an hour at mid-northern latitudes, so fewer people are born with it rising. That makes it one of the rarer rising signs up north. In the Southern Hemisphere the pattern flips: Aries rises slowly there, and it's one of the more common ones.
Questions
What does an Aries rising look like?
Tradition gives Aries rising a strong brow and a quick, forward-leaning walk. In practice the giveaway is pace: you move, speak and decide faster than the room.
Is Aries rising the same as being an Aries?
No. "Being an Aries" means your Sun was in Aries. Aries rising comes from the hour and place you were born, so it turns up with every Sun sign.