If there’s one TV hairstyle that’s stood the test of time, it’s Thomas Shelby’s undercut from Peaky Blinders. Barbers around the world still get daily requests for this sharp, structured look — a mix of discipline, rebellion, and pure vintage cool. It’s bold yet minimal, the kind of cut that makes you look like you mean business the moment you walk into a room.
Cillian Murphy’s portrayal of Thomas Shelby brought more than great dialogue and gritty charm — his haircut became part of the character’s power. The tight sides and slicked-back top reflected Shelby’s personality perfectly: clean, precise, and just a bit dangerous. Whether you’re drawn to it for the classic style or the gangster edge, there’s a reason this haircut keeps trending years after the show’s finale.
In this guide, you’ll learn exactly how to get the look — from what to tell your barber to how to style and maintain it.
Understanding the Thomas Shelby Undercut
The Peaky Blinders haircut is built around one key principle — disconnection. The sides and back are cut extremely short or even shaved, while the top stays longer and is slicked straight back. There’s no gradual blend between the two areas — that sharp contrast is what makes it instantly recognizable.
Key Features
- Disconnected sides: This is the signature Shelby look. The difference in length between the top and sides is deliberate and dramatic.
- Length on top: Usually medium to long (about 4–6 inches), styled back for volume and control.
- No fade or blend: Unlike modern fades, this cut keeps a clear divide — the top almost looks like it sits on a different layer of hair.
Historical Roots
Back in the early 1900s, this haircut wasn’t just for style. Working-class men — including real street gangs like the Birmingham Peaky Blinders — favored it for practical reasons. Short sides helped prevent lice and made it easier to clean up after a day’s work, while the longer top allowed a bit of individuality and swagger. It was functional, intimidating, and surprisingly modern for its time.
Guide: How to Ask Your Barber for the Cut
Getting the Thomas Shelby undercut right starts with clear communication. Barbers love the reference, but they’ll need the details to nail it exactly like Cillian Murphy’s version. Here’s how to break it down.
The Sides – Go for Full Disconnection
Ask for clippers on a #1 or #2 guard, depending on how extreme you want the contrast. If you want a sharper, more dramatic Shelby look, go with a #0 or skin shave on the sides and back. Make sure to emphasize no blending. The line between the top and sides should be straight and bold — that’s the defining element of this cut.
The Top Length – Keep It Medium and Movable
The top should be around 4–6 inches long — enough to slick back cleanly without falling flat. Ask your barber to keep the top layered lightly for natural movement instead of leaving it blocky or too thick. This helps you style it back easily while keeping volume and flow.
The Hairline – Sharp, Clean, and Square
Request a square finish at the neck and temples to keep the structure tight. The overall shape should stay angular, matching the precision of Shelby’s demeanor. Avoid rounded edges — this cut is all about clean, defined lines.
Quick Tip
Bring a clear photo of Cillian Murphy as Thomas Shelby. Visual reference always beats description when it comes to classic cinematic hairstyles.
Styling & Achieving the Look
Once the cut is done, the real magic happens in the styling. The Thomas Shelby look is sharp but effortless — like you rolled out of bed looking dangerous. The goal is a clean slick-back with texture and volume, not a greasy, glued-down finish.
Essential Products
To get that authentic Shelby polish, you’ll need:
- Pre-styler: A sea salt spray or volume powder adds grit and lift before drying.
- Styling product: Go for a matte clay or low-shine pomade — this keeps it natural and strong without the glossy gel look.
- Finisher: A light mist of hairspray keeps the hold all day, especially if you’re out in the elements.
Step-by-Step Styling
- Start with clean, towel-dried hair. Keep it slightly damp for easier shaping.
- Spray sea salt or apply volume powder. This builds that dry, textured base.
- Blow-dry back and away from your face, using a round or vented brush to guide the shape. The motion should follow the direction you want the final slick-back to sit.
- Work a small amount of matte clay or pomade between your palms until it’s warm, then run it through from roots to ends. Focus on the top layer to keep things smooth and sleek.
- Finish with hairspray. A quick mist adds staying power without stiffness.
Avoid These Common Mistakes
- Skipping texture: Without pre-styling, the top may look flat.
- Using shiny gels: These kill the authentic, gritty Peaky Blinders vibe.
- Overloading product: Less is more — the cut should do the talking, not the wax.
Undercut Variations & Modernization
The classic Thomas Shelby undercut is timeless, but it’s also flexible. You can adapt it to modern styles without losing that tough, confident edge. Whether you want something more polished for work or a rugged version for everyday wear, these variations keep the spirit of the Shelby look alive.
The Modern Undercut – Subtle Blend
If the harsh disconnection feels too bold for your lifestyle, ask your barber for a soft blend instead of a hard line. This creates a smoother transition between the sides and top — perfect if you want the Peaky Blinders look without the full gangster intensity. It still keeps the structure but feels more wearable for daily settings.
The Textured Crop – Shorter and Grittier
Prefer something with less volume? Try a shorter top (around 2–3 inches) styled forward into a messy, textured crop. This version works great for thick or wavy hair and gives that effortlessly rough aesthetic that fits right into modern street style.
Longer Top – The “Arthur Shelby” Variation
For a bolder twist, grow out the top to around 7–8 inches and keep the sides clean-shaven. This gives a heavier, more dramatic sweep when slicked back, perfect for those who want a commanding, high-volume version of the cut.
No matter the variation, the essence stays the same — short, clean sides and a longer top that demands attention. The only question is how daring you want to go.
Maintenance and Upkeep
The Shelby haircut might look effortlessly cool, but keeping it sharp requires regular attention. Since it’s all about clean lines and contrast, you’ll need to stay consistent with trims and take care of the longer top to maintain its sleek finish.
Regular Barber Visits
To keep the sides crisp, plan a barber visit every 2–3 weeks. The undercut loses its edge quickly once the hair starts growing out, especially around the temples and nape. A quick cleanup between full cuts keeps it fresh and structured without needing a full restyle each time.
Keeping the Top Healthy
The longer top can dry out fast from frequent styling. Use a light conditioner after shampooing and a heat protectant spray before blow-drying. This keeps the hair soft, manageable, and prevents that straw-like texture that ruins the slick look.
Handling the Grow-Out Phase
When you’re ready to transition out of the Shelby undercut, talk to your barber about blending the sides gradually as they grow. This prevents the “mushroom effect” — where the longer top sits awkwardly on shorter sides. A few shaping sessions can turn the grow-out into a new, more relaxed style.
Conclusion
Cillian Murphy’s Peaky Blinders haircut isn’t just a style — it’s a statement. It blends clean structure with raw attitude, creating that unmistakable mix of power and precision Thomas Shelby is known for. With the right barber instructions, styling routine, and upkeep, you can bring that same confidence and edge into your everyday look.
Remember, this cut works best when paired with confidence. It’s not only about the hair — it’s about the posture, the suit, and the energy you carry. So whether you go for the classic disconnected undercut or a modern variation, own it completely.
Ready to try it yourself? Bring this guide — and a photo of Cillian Murphy — to your next appointment and let your barber do the rest. You might not be leading the Peaky Blinders, but you’ll definitely turn heads like one.
