I'm happy that Astrodatabank has convincingly confirmed his birth data and rated his chart AA as a result.
Peterson has a number of configurations which enable speedy chart interpretation. I start with Venus/Neptune/Jupiter grand trine because Venus is angular, the closest of any planet in his chart to As, Dc, Mc, or Ic. Conventional contemporary astrologers look to the ruler of the Ascendant as the "chart ruler", but I do not. The planet ruling the Ascendant is certainly important, but any planet close to a chart angle is more rightly the ruler, or "a" ruler. In fact, the grand trine itself is the ruler, Venus/Jupiter/Neptune. Of course, in this case, the planet ruling is one and the same whether you consider the ruler of Taurus on the Ascendant or whether you note the most angular planet, Venus in both cases. Dubbing a configuration as a chart ruler actually hastens and improves the interpretation because it offers the specificity of three planets together rather than a lone singleton.
Peterson has very high ideals about the human race, and he feels it as a humanitarian love. Mystics might say he possesses a high, refined love for humankind. It is this more than anything else that attracted him to psychology. He is a Canadian psychology professor and a practicing clinical psychologist. It is this grand trine, not his ideas and opinions, that fuels his popularity (Venus/Jupiter). His audience senses his love for his fellow humans. While his chart is afflicted in many ways, this suggests that he has experienced much happiness, if not bliss, in his life.
A side effect to this might be involvement with aesthetics and beauty. He is more platonic than romantic unless we find some contradiction elsewhere, but he is warm-hearted. [His Mars/Venus quintile is certainly romantic.]
There is the grand trine Mercury/Saturn/Moon, but Sun, due to its proximity to Mercury and its involvement in the grand trine, is another grand trine (Sun/Saturn/Moon). Since Saturn is accentuated by both Sun and Moon together, it is a second candidate for chart rulership, or a co-ruler, if you will. Wide, skew grand trines are quite legitimate and instrumental to interpretation. The fact that it is not a close grand trine means that it is not an affliction. However, the Mercury/Saturn/Moon grand trine is much closer and challenging to call on this count. Nonetheless, it seems the grand trines have helped ease the afflictions of the Mars/Saturn/Neptune T-square.
In fact, though it is Saturn that is promoted by its involvement with both Sun and Moon together (another recipe for rulership), the close proximity of South Node to Saturn is somewhat inseparable and helpful for interpretation with more specification to offer. Saturn alone could mean many things, but Saturn/Node is more focused, articulated, and specific. Saturn/Node is common in teachers and organizers. Sometimes it suggests conservative topics and views. Saturn opposed lunar node suggests someone who can be surly; who will cut fools down to size fast; who has a sharp distaste for nonsense. Such people are often widely hated, but they are loved and admired as they mature into old age.
We cannot neglect the Moon/Saturn trine which suggests a sober nature that does not easily express warmth or trust, not to say that such does not exist, it is just not displayed as a rule. This sober nature will enable him to be more helpful to people who might need his help.
The Sun/Saturn trine shows that he does not believe in luck, and he doesn't count on luck, but he is willing and able to work toward his goals in smaller more sensible steps than others more optimistic might do.
The entire grand trine Sun/Moon/Saturn speaks of his partner, particularly a marriage partner. He met his wife when they were young, and he accepted her without dating around and exploring other relationships. He considers himself lucky, I believe, that he found a good mate early on. They have a stable long-term relationship, but she has been a burden due to her ill health, also symbolized by Saturn at the Sun/Moon midpoint. Saturn often symbolizes practical obstacles like distance, blockage, and age.
Since Peterson is not known as a singer, his Mercury/Moon/Saturn grand trine speaks of his public speaking, and the ease and reward he has encountered in that path. As a side-effect, he will deal with depression--both his own and others. This is much reinforced by the Saturn/Neptune square. The Mercury/Saturn trine suggests a philosophical bent. Peterson relies heavily upon friends to advise and critique his talks. The Saturn involvement would curtail his confidence in that area. He is probably talkative (Mercury-square-Jupiter reinforces this indication) and also a bit ashamed of being talkative. He thus goes through taciturn moods as a form of compensation.
The Mars/Saturn/Neptune T-square is next by virtue of its ominous closeness. He may do much damage to himself through substance abuse. He admits that he was an abuser of alcohol while young, and his road to recovery was long and hard. He is otherwise inclined to ill-health. He may have an adverse reaction to prescribed drugs that are considered helpful to most others who take them. He struggles with his introspective suffering, and he struggles with others who deal with introspective suffering. Despite his intellectual efforts, there is doubt and confusion about what is or is not real. There may be considerable bitterness. There is a tendency to start and stop with his progress. He may have a burst of energy and then withdraw as if to conserve that energy. He has struggled with a feeling of inferiority.
The T-square Mercury/Jupiter/Pluto is his psychological (Pluto) scholarship (Mercury/Jupiter). He is a psychology professor with a Phd. in his field (if they have Phd.'s in Canada). The side-effect of this is a tendency to be driven. Others may be disconcerted by his driven quality. He has a pronounced tendency to nag, fuss, and threaten. He may be obsessive about convincing unbelievers. Sun is drawn in again due to its proximity to Mercury, so we find Sun/Jupiter/Pluto which signals leadership qualities and a possible success on a large scale. Such pictures are common in millionaires. This is reinforced by Jupiter trine Neptune and Mars sextile Jupiter.