The Friesian is most often recognized by its black coat color, though color alone is not their only distinguishing characteristic. Friesian horses also have a long, thick mane and tail, often wavy, and "feathers"--long, silky hair on the lower legs, deliberately left untrimmed. The official breed rarely has white markings of any kind; most registries allow only a small star on the forehead for purebred registration. Though extremely rare, and not accepted for registration in most cases, Friesians are occasionally chestnut. The Friesian's average height is about 15.3 hands (63 inches or 1.60 m), although it may vary from 14.2 to 17 hands (between 58 in./1.5 m and 68 in./1.7 m) tall at the withers, and mares or geldings must be at least 15.2 hands (1.57 m) tall to qualify for a 'star-designation' pedigree. The breed is known for a brisk, high-stepping trot. The Friesian is considered a willing, active, and energetic horse that is also gentle and docile. A Friesian tends to have great presence and to carry itself with elegance.

The breed has powerful overall conformation and good bone structure, with what is sometimes called a "Baroque" body type. Friesians have long, arched necks and well-chiseled, short-eared, "Spanish type" heads. Their sloping shoulders are quite powerful. They have compact, muscular bodies with strong sloping hindquarters and a low-set tail. Their limbs are comparatively short and strong. To be accepted as breeding stock in the FPS studbook, a stallion must pass a rigorous approval process.

Today, there are two distinct conformation types. The baroque type has the more robust build of the classical Friesian. The modern, sport horse type is finer-boned. Conformation type is judged less important than correct movement, and both types are common, though the Modern type is currently more popular in the show ring than is the Baroque Friesian.