Klingon society was extremely complex. Before its decline in the mid-22nd century and again in the late 23rd century, Klingon society was based on a feudal system organized around traditional Great Houses of noble lineage, to which various parts of the population owed fealty. The Great Houses are traditionally represented in the Klingon High Council, which was led by a Chancellor, replacing the heredity leader of Emperor.
The decline of Klingon culture was demonstrated in the acts of the Klingons themselves. They stopped caring about their weapons to the point that they let them rust and even stopped caring for true honor. Sometime after the augment virus took hold of the Klingon Empire, a new regime took control, turning the Empire into an authoritarian state that kept tabs on all who served. The old ways returned in the latter 23rd and early 24th centuries respectively.
Males traditionally dominated public life in the Empire, assuming the leading roles in politics and the military with only rare exceptions. (TNG: "Redemption") There were three notable exceptions to the prohibition of women serving on the High Council. In 2257 L'Rell rose to High Chancellor and Dennas served on the High Council. The third instance occurred in 2293 when Azetbur became Chancellor of the High Council after her father, Gorkon, was assassinated. Women traditionally dominated the household and the management of the family's affairs Klingon women were treated as equals, except in politics and matters of inheritance. Law prohibited them from serving in the High Council and they could not take control of their Houses unless they had the money and no male successors of the lineage. Otherwise, Klingon women were expected to exhibit the same physical prowess and lust for blood and honor as the men.
Klingon society functioned through a system of family reputation and honor. Tradition was an integral part of their lives and breaking from observances was considered a grievous insult to society, an insult not forgotten easily. An offense usually brought shame to the offender's name for several generations. The highest shame was discommendation, an action by the High Council to officially strip a Klingon of his personal or family honor. Bloodlines and relations were also taken very seriously by any "true" Klingon. Lines comprised more than mere family members.
The military was integral to Klingon society, as it provides opportunities for warriors to die in battle. For the same purpose, the Empire often seeks to expand through conquest. Discipline was strictly enforced, by one's superiors and subordinates both; the latter may assassinate his superior and take his place. This gives Humans the false impression that there are no rules, but in fact, this can be done only under certain conditions, dereliction of duty and cowardice among them, and the challenge can be made only to a direct superior.
An integral part of tradition was the various rituals that marked milestones in a Klingon's life or the history of the Empire. Most notable of the rites was the Rite of Succession, which a future leader of the Empire had to complete with a valid Arbiter of Succession (Captain Jean-Luc Picard, in the case of Gowron) overseeing the proceedings. Before the Rite could begin, there was another elaborate ceremony needed to confirm the death of the previous leader. This was known as the Sonchi ceremony. Individual Klingon warriors were expected to go through the Rite of Ascension to be recognized as a full adult. If the house that an individual Klingon belonged to was dissolved or fell into dishonor, he could be adopted into another house through the R'uustai or alternative ceremonies that symbolically marked the joining of kinship and allegiance.. The Right of Vengeance, allowed Klingons to seek redress for the deaths of their family members by engaging the one responsible in single combat. The right was so important, that even the discommended could claim it against important political figures, as the discommended Worf was able to challenge Duras (a candidate for the title of Chancellor.
Klingons were extremely territorial. According to the first known Klingon linguist, there was no such thing as an "insignificant corner of Klingon space".
Skin colors ranged from olive, brown, and black to pearlescent/metallic across the entire spectrum of the rainbow, varying from purple, pink, burgundy red, yellowish tan, dark orange, umber brown, grey, blue, dark green, coal black, and chalky white. Their skin had a shimmery slick metallic semi-reflective sheen to it. Albino Klingons were often considered outcasts in Klingon society.
Klingon children matured far more quickly than Human children. At the age of only one Earth year, a Klingon child had the appearance a Human child had at about four. By the age of eight Earth years, a Klingon attained the maturity a Human did not reach until about age sixteen. When Klingon children began growing into adults, they went through jak'tahla, a Klingon form of puberty. Like other mammalian species, Klingon females were capable of lactating to breast-feed infants. Klingons tended to live for over 150 years. Even into advanced old age, Klingons were usually still strong enough for combat, but were still susceptible to various mental conditions associated with old age.
Klingons were notably stronger than most humanoids, at least as strong as Vulcans. However, despite their endurance and general robustness, they had a considerably lower tolerance to the cold than humans. The Klingon sense of smell was notably acute; in fact, it was powerful enough to be used effectively to track down prey during a hunt. Their sense of smell was also suggested to play an integral role in their mating practices.