The GMC Sierra HD is the mechanical twin of the Chevrolet Silverado HD. The difference is that the GMC has a different aesthetic and a diverse model range that’s more upscale than the Chevy. The off-road-ready AT4 variants and luxurious Denali trims make the Sierra HD stand out in a competitive class of heavy-duty trucks, including the Ford Super Duty and Ram HD.

With various cab sizes, trims, and options available, the interior of the Sierra HD can vary quite a bit. What they all have in common are ergonomic controls, comfortable front seats, and modern technology, including in the lower trims.

Let’s take a closer look at the inside of the GMC Sierra HD.

Passenger Room and Comfort

Big trucks with big cabs have big interiors. The GMC Sierra HD is no exception. No matter which of the three cab options you choose, every Sierra HD has pleasantly roomy front seats. GMC knows that many owners of these trucks regularly make long hauls, and the front seats are designed accordingly. The Sierra HD has more front legroom and headroom than its rivals from Ford and Ram, making it a comfortable choice for taller drivers.

Since the Crew Cab is the most popular cab option for this truck, that’s the one we’ll focus on. With 43.4 inches of legroom and 40.1 inches of headroom, backseat passengers have plenty of room to stretch out. That’s about the same backseat space as the Ford Super Duty SuperCrew and a little more legroom than the Ram HD Crew Cab. However, the Ram offers the MegaCab option that puts rear legroom on par with Ford and GM, plus some storage space behind the back seats.

If you go with the Double Cab option, the backseat legroom in the Sierra HD shrinks to 35.2 inches. That’s a little cramped but roomier than the Ford Super Duty SuperCab. Even the GMC Terrain compact SUV has more rear legroom than that. However, it’s fine if you only occasionally have backseat passengers and just want more space than the Regular Cab.

Notably, the Regular Cab and Double Cab are only available with the Pro and SLE trims. Every other trim of the Sierra HD comes standard with the Crew Cab.

Features and Tech

All but the base Pro trim comes with a gorgeous 13.4-inch touchscreen and a 12.3-inch digital gauge cluster. These customizable screens work in concert to deliver all the information you need, and their user-friendly interface has a short learning curve. The base Pro trim uses a 7-inch screen, and wireless Android Auto and Apple CarPlay are standard in both systems.

To give you an idea of just how versatile this model range is, the audio system in the GMC Sierra HD can have as little as two speakers and as many as 12. The lower trims have either two or six speakers depending on the cab, while the AT4 and Denali trims all use a 7-speaker Bose system. The AT4X and Denali Ultimate models upgrade to a rich, 12-speaker Bose Premium Series system.

The Sierra HD is available with all the modern features you’d expect in a premium pickup, like heated, ventilated, and massaging front seats, a wireless charging pad, a head-up display, and the latest safety tech. A few interesting features you might not expect include a Kicker in-bed audio system and ProGrade Trailering Tech with up to 14 available camera views. This simplifies the hitching process and lets you see everything happening around your trailer with a Transparent Trailer View option, allowing you to effectively see through the trailer on your screen.

Materials and Design

This interior’s rugged yet premium design perfectly speaks the GMC design language. We love the multifunction steering wheel, the old-school column shifter, and the user-friendly knobs on the dash, but the Sierra HD is also an uncompromising luxury vehicle in the upper trims.

Working your way up the trims of the Sierra HD makes this truck more luxurious. The Pro trim has standard vinyl seats (cloth is optional), the SLE and SLT trims have cloth seating (leather is optional on SLT), and the AT4, AT4X, Denali, and Denali Ultimate trim all come standard with perforated leather seating.

Some design elements of this interior can change quite a bit depending on the trim. For example, the AT4 model has a Jet Black interior with Kalahari accents, while the AT4X model boasts a stylish Obsidian Rush full-grain leather interior with authentic Vanta Ash wood trim. 

Meanwhile, the Denali models live up to their reputation. The Sierra HD Denali has perforated leather seating surfaces, complemented by open-pore wood and patterned aluminum trim. Going to the top Denali Ultimate trim gets you the Alpine Umber full-grain leather interior with open-pore Paldao wood. Topographical map patterns of Denali’s summit are etched into the leather and wood.

Cargo Room and Flexibility

While the bed isn’t technically part of the interior, the bed size options are worth a mention. The Standard Bed is 82.25 inches long, and the Long Bed is 98.27 inches long. Also worth mentioning is one of our favorite GMC features: the six-function MultiPro tailgate, which can turn into steps, load stops, a desk, and more.

As for the cab, there’s no shortage of generously sized cubbies and consoles throughout. You get a clever under-seat storage system if you opt for the popular Crew Cab. Jumper cables, ratchet straps, sports gear for the kids, or even fishing poles fit nicely under the back seats so they don’t slide around in the bed. In the Double Cab, the bottoms of the rear seats easily fold up for extra in-cab storage space.

Build and price your own version of the 2024 GMC Sierra HD to see this week’s Kelley Blue Book Fair Purchase Price, or check out GMC Sierra HD models for sale near you.