Although a rare breed today, during the 1920s and 1930s the breed enjoyed popularity and was owned by Gary Cooper, Cary Grant, Humphrey Bogart, Richard Burton and Alfred Hitchcock whose own Sealyhams can be seen in his films "The Birds" and "Suspicion". Sealyhams also were a popular subject for postcard artists during this period.

The Sealyham is a double-coated breed with a soft undercoat and a harsh, weather-resistant outer coat and requires regular coat maintenance For the showring the Sealyham is hand stripped - the long and dead hairs are plucked out by hand. The stripping process is time-consuming but the coat of the Sealyham kept purely as a companion can be clipped. The luxurious furnishings on the head, legs and chest require regular brushing to eliminate knots and tangles.

The clown of terriers, the Sealyham is a loyal, intelligent, sometimes stubborn but always devoted companion, and although most terriers are ʻbusyʼ dogs, the Sealyham is the couch potato of the Terrier world, having a much more relaxed attitude.

The Sealyham is a large dog in a small package and makes an ideal companion for both city and country living and a moderate amount of exercise will keep him fit.