INTJs are analytical. Like INTPs, they are most comfortable working alone and tend to be less sociable than other types. Nevertheless, INTJs are prepared to lead if no one else seems up to the task, or if they see a major weakness in the current leadership. They tend to be pragmatic, logical, and creative. They have a low tolerance for spin or rampant emotionalism. They are not generally susceptible to catchphrases and do not recognize authority based on tradition, rank, or title.

Hallmarks of the INTJ include independence of thought and a desire for efficiency. They work best when given autonomy and creative freedom. They harbor an innate desire to express themselves by conceptualizing their own intellectual designs. They have a talent for analyzing and formulating complex theories. INTJs are generally well-suited for occupations within academia, research, consulting, management, science, engineering, and law. They are often acutely aware of their own knowledge and abilities—as well as their limitations and what they don't know (a quality that tends to distinguish them from INTPs). INTJs thus develop a strong confidence in their ability and talents, making them natural leaders.

In forming relationships, INTJs tend to seek out others with similar character traits and ideologies. Agreement on theoretical concepts is an important aspect of their relationships. By nature INTJs can be demanding in their expectations, and approach relationships in a rational manner. As a result, INTJs may not always respond to a spontaneous infatuation but wait for a mate who better fits their set criteria. They tend to be stable, reliable, and dedicated. Harmony in relationships and home life tends to be extremely important to them. They generally withhold strong emotion and do not like to waste time with what they consider irrational social rituals. This may cause non-INTJs to perceive them as distant and reserved; nevertheless, INTJs are usually very loyal partners who are prepared to commit substantial energy and time into a relationship to make it work.

As mates, INTJs want harmony and order in the home and in relationships. The most independent of all types, INTJs trust their intuition when choosing friends and mates—even in spite of contradictory evidence or pressure from others. The emotions of an INTJ are hard to read, and neither male nor female INTJs are apt to express emotional reactions. At times, INTJs seem cold, reserved, and unresponsive, while in fact they are almost hypersensitive to signals of rejection from those they care for. In social situations, INTJs may also be unresponsive and may neglect small rituals designed to put others at ease. For example, INTJs may communicate that idle dialogue such as small talk is a waste of time. This may create the impression that the INTJ is in a hurry—an impression that is not always intended. In their interpersonal relationships, INTJs are usually better in a working situation than in a recreational situation.