Straight-laced and serious-minded, there’s a reason Kate Middleton was able to blend so seamlessly into the rule-following, traditional role of Duchess of Cambridge; her personality type might just be perfectly suited to wearing that crown.

Based on an analysis of her observed behavior and motivations, Kate is most likely an Enneagram Type One, and an ISFJ personality type. Here’s what makes the Duchess of Cambridge so unique. 

Enneagram Type One: The Perfectionist 

As a Type One, Kate is organized, reasoned and perfectionstic. As a devoted public servant, and patron of many charitable causes, she has a strong motivation to do good in the world and do right by others. She is mission-focused, and can work tirelessly toward a singular goal.

Ones constantly seek self-improvement, and can often dwell on mistakes. They are hard workers, good friends and spouses, and natural nurturers and caretakers. Key characteristics of Type Ones: Wise, ethical, diligent, purposeful, driven, desire to do right, fear of doing wrong.


  • Kate is perfectionistic and proper, and rarely shows vulnerability or mistakes.
  • Much has been said of Kate’s always-polished fashion choices, usually appearing as the epitome of grace and poise whether she’s walking a red carpet or grabbing groceries.
  • She doesn’t seek the spotlight, and doesn’t often give speeches or speak on camera.
  • Kate is humble and approachable, for instance, leaving personal comments on photos from her “Hold Still” pandemic project this past summer, and signing her name “C.” She even jumped on a podcast early in 2020, focusing on motherhood.
  • The Duchess is methodical and principled in her role, always ready to “step up to the plate” when she’s called upon for an assignment. She’s made numerous overseas tours on behalf of The Queen, from Kenya to Namibia, Pakistan to Sweden, and beyond. 
  • The royal historian Sally Bedell Smith summarizes The Duchess’ public persona aptly: “She also has a natural ability to blend accessibility and dignity with a royal mystique that shields her privacy—a tough line to navigate.” A true Type One trait.


  • Ones are mission-focused and charitable; Kate focuses on causes that matter a great deal to her, like children and family, mental health, sports and arts. She takes seriously her duties to the crown and to the country in this respect, including myriad efforts in 2020 to help Britons cope with the pandemic, from delivering meals to those homebound or saluting frontline healthcare workers.
  • Ones are often driven by their goals, and Kate has a clear one. Since she married Prince William in 2011, she’s been preparing for her eventual role as Queen of the United Kingdom. 
  • Family is very important to The Duchess, from her nuclear family with her children, to her broader familial relationships; for instance, she’s very close to her sister, Pippa.
  • A typical Type One, Kate has high standards of excellence. She is driven and focused, “a hard worker and very conscientious,” according to her past teachers and mentors -- both as a student, and as an athlete. 

Myers-Briggs Type: ISFJ (The Protector)

ISFJs are loyal, humble, thoughtful types, who are conscientious and kind-hearted. They often love to play helper versus taking center stage -- much like Catherine, Duchess of Cambridge displays in her understated public work. ISFJs are known for their adherence to tradition, focus on family, and an unassuming approach to career and interpersonal relationships.

I / Introverted: Kate tends toward the shy end of the spectrum, and likes to stay out of the spotlight as much as she can. She has a few friends and family that she’s very close to, but is comfortable on her own, and often enjoys solitary hobbies.  

S / Sensing: Grounded, hard-working and factual, Kate tends to be principled and rational in her approach to the world. She is a doer and executor, who likes to put plans into motion.

F/ Feeling: Kate makes decisions and creates goals by following her heart. You can see many of the charitable causes in which she participates -- mental health, children, sports -- are things she’s been actively involved in for years, and very humanity-focused.

J / Judging: Organized and structured, The Duchess tends to like order, rules and clear benchmarks she can set her sights on. This trait has helped her meld into royal family life, where expectations are highly regimented.

ISFJ Cognitive Functions

Si: Often focused on preserving tradition, Kate is a stickler for rules, closely guards her family, and follows past precedent when making decisions. 

Fe: Concerned with harmony above all else, Kate doesn’t rock the boat. She simply wants everyone to get along. You’ll rarely see her get upset or angry publicly, and she’d rather bite back her real feelings than see them cause a rift between loved ones.

Ti: Introverted Thinking equates to a unique way of rationalizing the world, and a thirst for knowledge. Kate has a love of reading, and varied interests, from gardening, to photography, to sailing.

Ne: This is the trait with which ISFJs like Kate are least comfortable: Extroverted Intuition (Ne), which is all about seeing and exploring possibilities. We see her tap into this function most commonly as she embraces new cultures during her travels. 

In many ways, The Duchess’ personality is uniquely suited to her current role as princess, and her future role as Queen. This Type One/ISFJ is duty-bound, goal-focused and rule-inclined, all traits that will continue to allow her values to shine through as she ascends her (eventual) throne. 

Fast Facts on ISFJs:

  • ISFJs are the most common type in the U.S., and the most common type among women
  • 14% of the general population; 19% of women and 8% of men
  • Described commonly as “Conservative,” “Conventional, “Guarded,” “Reserved”
  • Among the types to most commonly believe in a higher spiritual power
  • More likely than average to experience chronic pain and heart disease
  • One of the top 2 most common types to major in “education” in college
  • Overrepresented among MBAs and male small business owners
  • Personal values: “Happy family,” “Health” “Spirituality”
Jenna Birch
Jenna Birch is a content and brand strategist for startups, entrepreneurs and VCs. Before moving into consulting, she was a prolific journalist for national magazines and websites, and author of The Love Gap: A Radical Plan to Win in Life & Love (Grand Central Publishing). Her work has been published in The Washington Post, Vogue, Cosmopolitan, Marie Claire, Harper's Bazaar, InStyle, HuffPost, and more. She lives in Ann Arbor, MI with her EXTP fiancé and the best pup around, Ollie.