Quick answer to how long do you cook chicken legs on the grill: At least 20 minutes.
How long it takes to grill chicken legs depends upon the size of the chicken legs. It could take between 20 and 40 minutes on a medium heat grill. You will know that the chicken legs are finished cooking when the juices become a clear, transparent color. Using a meat thermometer, the internal temperature of a properly cooked chicken leg is 180 degrees Fahrenheit. To decrease the cooking time of the chicken, boil the legs for 10-20 minutes before placing them on the grill for the a final 10 minutes of crisping.