Lacy dogs are strong and fast, lightly built but proportional within the height-to-weight ratio. Height at the withers is from 43 to 56 cm (17 to 22 in). Dependent on height and general conditioning, weight should be approximately 11 to 20 kg (25 to 45 lb) for females and 16 to 25 kg (35 to 55 lb) for males. The standards listed in the Texas House Concurrent Resolution No. 108 are slightly different: height between 46 to 64 cm (18 to 25 in), weight between 14 to 23 kg (30 to 50 lb) but it was not until 2005 that it was official
Blue Lacy Dogs in general are intelligent, intense, active, and alert. Developed to be both hunting and herding dogs, they display great drive and determination to work with big game and control difficult livestock. Young dogs may have too much energy and drive for small children. They are easy to train, learning new skills quickly.
Lacys are generally very healthy dogs. Developed for generations to meet the requirements of ranchers and hunters, they are sturdy enough to withstand tough terrain, difficult working conditions, and both hot and cold weather by Texan standards. However, skin problems and food allergies can occur. Color dilution alopecia is very rare but has occurred in Lacys