17 Famous People Who Kept a Journal: From Kings to Geniuses

Did you know that throughout history, some of the most influential minds kept a journal?

Writing helped them to think, decide, lead, and understand themselves better.

In modern times we often think of journaling as a form of self-expression. For many great thinkers, however, it was a private laboratory for ideas, ethics, creativity, and strategy.

Let's take a look at 17 well-known figures who kept journals and what they used them for, along with how you can apply the same principles using Mindsera.

1. Eileen Gu

To analyze thinking and shape who she becomes

Eileen Gu is known for elite performance both as a freestyle skier and academically. She recently won Olympic gold and holds the record for the most Olympic medals in her discipline. A Stanford student with an SAT score of 1580/1600, she's spoken about journaling as a key tool for introspection. Her goal is to become someone her younger self would admire.

How Mindsera helps:
Mindsera's GROW Model framework is a structured process for setting and achieving goals. It helps you identify where you are now, where you want to be, what options you have to get there, and what actions you'll take to make it happen.

2. Anne Frank

To process fear and preserve identity

Anne Frank wrote one of the most famous diaries in history while hiding from Nazi persecution during World War II. Her journal helped her navigate fear, uncertainty, and the challenges of adolescence under extreme circumstances. For Anne, writing was a way to maintain a sense of normal life, reflect on her thoughts and feelings, and preserve her identity in a world that threatened to erase it.

How Mindsera helps:
Mindsera's Emotion Audit framework helps you understand why you're feeling a certain way. It's ideal for when you're experiencing a strong emotion and want to get clarity and some relief.

3. Frida Kahlo

To express emotion and explore identity

Frida Kahlo was a groundbreaking Mexican painter known for her bold, surrealist-inspired self-portraits and deeply personal artwork. She kept a private journal filled with sketches, poems, and reflections on pain, politics, and identity. Her journal was both a creative outlet and a tool for self-exploration, blending art and writing to process emotions and experiences.

How Mindsera helps:
Mindsera allows you to attach images to your entries for a very personal journaling experience. Mindsera's analysis also generates original artwork based on your writing.

4. Susan Sontag

To develop ideas and sharpen intellect

Susan Sontag was a celebrated writer, philosopher, and cultural critic whose essays and books shaped modern thought. She kept extensive notebooks and journals throughout her life, using them as a space to explore ideas, test arguments, and reflect on culture, politics, and identity. For Sontag, journaling was a private space for thinking, helping her clarify ideas before they became published works.

How Mindsera helps:
Mindsera's Design Thinking framework helps you minimize the risk of creating products or services that don't meet the needs of your users.

5. Marcus Aurelius

To reflect on life

The Roman emperor's Meditations was never meant for publication. It was a private journal where he examined his reactions, impulses, responsibilities, and mortality. He used writing to practice Stoicism and steady his character.

He wrote to remind himself who he wanted to be.

How Mindsera helps:
Mindsera's Stoic Principles Mind comments help you cultivate emotional strength and rational thinking.

6. Charlie Munger

To refine thinking and decision-making

Munger has spoken often about the importance of writing to clarify thought. He uses mental models and disciplined reasoning to avoid cognitive errors.

Writing slows thinking down. Slower thinking reduces mistakes.

How Mindsera helps:
The Thinking Traps Mind analyzes your entries for cognitive distortions and biased reasoning, helping you sharpen judgment.

7. Theodore Roosevelt

To reflect and lead with clarity

Roosevelt journaled consistently throughout his life. Even during times of grief and political pressure, he used writing to process emotions and maintain direction.

Leadership requires emotional steadiness.

How Mindsera helps:
The End the Day framework helps you reflect on decisions, emotional reactions, and lessons learned. Over time, this builds clarity and resilience.

8. Benjamin Franklin

To cultivate virtue and self-discipline

Franklin tracked his virtues daily, marking where he succeeded or failed. He treated self-improvement like a system and relied on structure, not just motivation.

How Mindsera helps:
With custom frameworks, you can design your own virtue-tracking system and review it weekly using Insights to see behavioral patterns over time.

9. Abraham Lincoln

To clarify thoughts and moral convictions

Lincoln often wrote 'hot letters' he never sent. Writing allowed him to cool emotional reactions and think more clearly before acting. For him writing things down was a way to curb impulsive leadership.

How Mindsera helps:
The Go Deeper feature helps you unpack emotional triggers before responding. Why not use it before sending a scathing email? It might change your perspective and save you a lot of bother (and regret) later on.

10. Elon Musk

To solve problems

Musk is known for breaking down complex problems into fundamentals. While not publicly associated with journaling, structured thinking and written reasoning play a central role in first-principles problem solving.

Writing forces problems into parts.

How Mindsera helps:
The Problem-Solving frameworks such as First Principles Thinking and Musk's 5 Step Design Process guide you through breaking down challenges step by step so you can approach decisions methodically.

11. Sam Altman

To make better decisions

Altman has discussed writing as a tool for improving clarity and judgment. Decision-making improves when thoughts are externalized and examined.

Many poor decisions stay internal and unchallenged.

How Mindsera helps:
Mindsera's Decision-Making frameworks help you articulate trade-offs, risks, and long-term implications before committing.

12. Naval Ravikant

To sharpen judgment and self-awareness

Naval often emphasizes self-awareness and clear thinking. Writing allows you to observe your own patterns instead of being unconsciously driven by them.

The more you learn about yourself, the more it helps you grow over time.

How Mindsera helps:
Insights tracks emotional and thematic patterns, helping you see recurring triggers and blind spots.

13. Leonardo da Vinci

To explore ideas and inventions

Da Vinci's notebooks were filled with sketches, observations, questions, and inventions. He wrote to explore curiosity without immediate pressure to publish or perform.

Creativity thrives in private experimentation.

How Mindsera helps:
Mindsera's writing mode combined with AI follow-up questions encourages exploration while helping you push ideas further. You can also add photos to your journal, similar to how Da Vinci included sketches in his notebooks.

14. Isaac Newton

To develop and test theories

Newton kept extensive notebooks while developing calculus and the laws of motion. His journals allowed him to test assumptions and refine theory over time.

Most breakthroughs happen step by step, not in one jump.

How Mindsera helps:
Mindsera's Entry Analysis helps you track your thought patterns and reasoning, offering insight into how you approach problems and helps refine your mental models over time.

15. Marie Curie

To improve scientific discovery

Curie documented experiments and research rigorously. Scientific progress depends on careful recording and reflection.

Clarity in documentation supports clarity in discovery.

How Mindsera helps:
The Weekly Review email gives you an overview of your progress and an analysis of the past week's activity, helping you make new discoveries about the way you think.

16. Christopher Columbus

To record travels and exploration

Columbus kept detailed logs of his journeys. Journaling preserved observation and discovery.

Recording experiences transforms them into knowledge.

How Mindsera helps:
Mindsera's voice journaling feature allows you to capture experiences in real time, especially when writing feels too slow (or when you're captaining a ship like Christopher).

17. Virginia Woolf

To process life and fuel creativity

Woolf used her diary to process daily life and develop creative ideas. Her journals gave her emotional clarity and artistic depth.

Creative work is often born from reflection.

How Mindsera helps:
Mindsera's Emotion insights help you understand the emotional tone of your writing, giving you deeper insight into how mood shapes creativity.

Why so many great minds journaled

Across the centuries, journaling has consistently served the same fundamental purposes: it clarifies thought, sharpens moral judgment, hones ideas, improves decision-making, helps process emotions, and fuels creativity. While the tools and mediums may change, (most of us don't use quills anymore), the principle remains the same: writing extends your thinking, allowing you to explore ideas and emotions far beyond what silent reflection can achieve.

A modern journal for modern thinkers

Most of the iconic names in this article used pen and paper because that was the best tool available. Today, we can go further. Mindsera combines structured reflection, cognitive analysis, emotional insights, and long-term pattern tracking. When you use Mindsera to journal, you're building a system for clearer thinking. Perhaps you want to lead better, decide smarter, create more, or understand yourself deeply. Whatever your goal may be, journaling remains one of the most powerful tools available. The difference now is that your journal reflects back.