Hi, I'm Justin.
London based Product Designer of 12+ years
Current
Staff Product Designer at Not On The High Street
Previous
Lead Product Designer at Growth·Design
Lead Product Designer at Bother
Founding Product Designer at Trutify
Product Designer at TouchNote
Other
Creator of Make Like The Greats (Podcast with 100,000+ listens)
Founder of Appfilm Media (Started at age 14)
Media Coordinator for IUFoST Conferences (x3)
Current
Staff Product Designer at Not On The High Street
Previous
Lead Product Designer at Growth·Design
Lead Product Designer at Bother
Founding Product Designer at Trutify
Product Designer at TouchNote
Other
Creator of Make Like The Greats (Podcast with 100,000+ listens)
Founder of Appfilm Media (Started at age 14)
Media Coordinator for IUFoST Conferences (x3)
A 30-sec intro…
A talk I gave on our product vision at All Hands, 2025
A talk I gave on our product vision at All Hands, 2025
An important life goal realised: Travelling Asia
An important life goal realised: Travelling Asia
Working with mentors: Dan and LX of Growth·Design
Working with mentors: Dan and LX of Growth·Design
Japan: Half my heritage, and most of my inspiration
Japan: Half my heritage, and most of my inspiration
My dad: a man who took work, and me, seriously
A fun, 1.5 min read...
The day I became a better designer
At 14, I built my first website and started earning money publishing articles online.
At 16, I joined a startup building software for retailers like M&S, Waitrose, and Uniqlo.
At 19, I dropped out* of UAL to design apps, websites, and tools for startups full-time.
I always knew software was powerful.
But over the next 10+ years, I realised something deeper.
The best-performing designs weren't just functional.
They tapped into human psychology.
Because UX doesn't happen on a screen…
It happens in the user's mind.**
So I went looking for the best minds to learn from.
Turns out I already knew who they were...
Alongside Kahneman, and Ariely, I'd been studying Growth.Design's case studies
to understand the behavioural principles that most shape UX.
So I emailed the founders, Dan and Louis-Xavier.
(With 130,000+ subscribers, I didn't expect a reply.)
They replied the next day.
Would I try making a case study in their style?
Hell yes.
They loved it.
Then came a second experiment: a hands-on format for teaching a concept deeply.
I did that too.
Within two weeks, I'd learned the truth of the old saying:
if you want to learn something, teach it.
59 emails later, we began working together.
At 14, I built my first website and started earning money publishing articles online.
At 16, I joined a startup building software for retailers like M&S, Waitrose, and Uniqlo.
At 19, I dropped out* of UAL to design apps, websites, and tools for startups full-time.
I always knew software was powerful.
But over the next 10+ years, I realised something deeper.
The best-performing designs weren't just functional.
They tapped into human psychology.
Because UX doesn't happen on a screen…
It happens in the user's mind.**
So I went looking for the best minds to learn from.
Turns out I already knew who they were...
Alongside Kahneman, and Ariely, I'd been studying Growth.Design's case studies to understand the behavioural principles that most shape UX.
So I emailed the founders, Dan and Louis-Xavier.
(With 130,000+ subscribers, I didn't expect a reply.)
They replied the next day.
Would I try making a case study in their style?
Hell yes.
They loved it.
Then came a second experiment: a hands-on format for teaching a concept deeply.
I did that too.
Within two weeks, I'd learned the truth of the old saying:
if you want to learn something, teach it.
59 emails later, we began working together.
During those next ~2 years, I made 14+ case studies on how psychology shapes:
(And more.)
This work sharpened my ability to design for how people actually behave, and to tie that to real business impact.
Dan and Louis-Xavier have also coached me personally, refining my instincts along the way.
Charlie Munger said:
"If you don't get psychology, you're not going to be a very good businessman."
Now I don't just get it.
I leverage it.
*Whilst I attended University of Arts London (LCC), studying Information and Interface Design (BA), I dropped out at 19 years old to pursue my preferred method of education: building real products for people with real business needs.
**The greatest insight to come out of the work of Growth.Design. Louis-Xavier and Dan break this down in depth in their course, Product Psychology Masterclass, which I also completed.
A fun, 1.5 min read...
The day I became a better designer
At 14, I built my first website and started earning money publishing articles online.
At 16, I joined a startup building software for retailers like M&S, Waitrose, and Uniqlo.
At 19, I dropped out* of UAL to design apps, websites, and tools for startups full-time.
I always knew software was powerful.
But over the next 10+ years, I realised something deeper.
The best-performing designs weren't just functional.
They tapped into human psychology.
Because UX doesn't happen on a screen…
It happens in the user's mind.**
So I went looking for the best minds to learn from.
Turns out I already knew who they were...
Alongside Kahneman, and Ariely, I'd been studying Growth.Design's case studies to understand the behavioural principles that most shape UX.
So I emailed the founders, Dan and Louis-Xavier.
(With 130,000+ subscribers, I didn't expect a reply.)
They replied the next day.
Would I try making a case study in their style?
Hell yes.
They loved it.
Then came a second experiment: a hands-on format for teaching a concept deeply.
I did that too.
Within two weeks, I'd learned the truth of the old saying:
if you want to learn something, teach it.
59 emails later, we began working together.
During those next ~2 years, I made 14+ case studies on how psychology shapes:
(And more.)
This work sharpened my ability to design for how people actually behave, and to tie that to real business impact.
Dan and Louis-Xavier have also coached me personally, refining my instincts along the way.
Charlie Munger said:
"If you don't get psychology, you're not going to be a very good businessman."
Now I don't just get it.
I leverage it.
*Whilst I attended University of Arts London (LCC), studying Information and Interface Design (BA), I dropped out at 19 years old to pursue my preferred method of education: building real products for people with real business needs.
**The greatest insight to come out of the work of Growth.Design. Louis-Xavier and Dan break this down in depth in their course, Product Psychology Masterclass, which I also completed.
Words from those I’ve worked with
Feedback from teams I’ve helped
“Always a fresh take - Justin is a pragmatic, critical thinker. There's always a clear process behind his designs and what problems they are trying to solve.”
Henriette Brand
Senior Software Mobile Engineer, Lendable
“Justin gets really engaged with all parts of business - trying to understand every challenge and constraint, and builds really strong relationships with the other team leads in the process.”
Lorin Minxhozi
Product Lead, Not On The High Street
“Justin is a very smart, driven and full of great ideas.”
Raphael Warner
Head of Video, Future Publishings
“There is no one I would recommend more than Justin for product design. His body of work speaks for itself.”
Konstantinos Askitopoulos
Principal Product Manager, Cobalt
“Can’t believe you took the time to do this. It’s really good.”
Tweet response to my podcast on making a great product.
Konrad Kay
Co-Creator of HBO’s Industry
Growth·Design
“…a brilliant mind, with so much desire to learn and create, it was refreshing to witness first-hand.”
Louis-Xavier Lavallee
Co-Founder, Growth·Design
“Justin is one of the most considered designers I've worked with. Every decision was intentional and held to a high standard. It would be a pleasure to work with him again.”
Belen Tahir
Senior Product Designer, Depop
“Justin is an incredibly thoughtful and intelligent designer. I've been blown away by his ability to think of new and inventive ideas to push our product further.”
Nick Baldwin
Design Lead, Apple Podcasts
“Justin more than a designer - he is a true product partner. Someone who take lead of initiatives and helps define the strategic roadmap. With Justin, you get someone who treats your business like his own.”
Michelle De Mott
Head of Product & Data, NOTHS
Growth·Design
“Justin brings empathy, curiosity, and a rare openness to growth to everything he does. I’ve honestly rarely seen someone so eager to get better every day.”
Dan Benoni
Co-Founder, Growth·Design
Words from those
I’ve worked with
Feedback from teams I’ve helped
“Always a fresh take - Justin is a pragmatic, critical thinker. There's always a clear process behind his designs and what problems they are trying to solve.”
Henriette Brand
Senior Engineer, Lendable
“Justin gets really engaged with all parts of business - trying to understand every challenge and constraint, and builds really strong relationships with the other team leads in the process.”
Lorin Minxhozi
Product Lead, NOTHS
“Justin is a very smart, driven and full of great ideas.”
Raphael Warner
Head of Video, Future Publishings
“There is no one I would recommend more than Justin for product design. His body of work speaks for itself.”
Konstantinos Askitopoulos
Principal Product Manager, Cobalt
“Can’t believe you took the time to do this. It’s really good.”
Tweet response to my podcast on making a great product.
Konrad Kay
Co-Creator of HBO’s Industry
Growth·Design
“…a brilliant mind, with so much desire to learn and create, it was refreshing to witness first-hand.”
Louis-Xavier Lavallee
Co-Founder, Growth·Design
“Justin is one of the most considered designers I've worked with. Every decision was intentional and held to a high standard. It would be a pleasure to work with him again.”
Belen Tahir
Senior Product Designer, Depop
“Justin is an incredibly thoughtful and intelligent designer. I've been blown away by his ability to think of new and inventive ideas to push our
product further.”Nick Baldwin
Design Lead, Apple Podcasts
“Justin more than a designer - he is a true product partner. Someone who take lead of initiatives and helps define the strategic roadmap. With Justin, you get someone who treats your business like his own.”
Michelle De Mott
Head of Product & Data, NOTHS
Growth·Design
“Justin brings empathy, curiosity, and a rare openness to growth to everything he does. I’ve honestly rarely seen someone so eager to get better every day.”
Dan Benoni
Co-Founder, Growth·Design
Words from those I’ve worked with
Feedback from teams I’ve helped
“Always a fresh take - Justin is a pragmatic, critical thinker. There's always a clear process behind his designs and what problems they are trying to solve.”
Henriette Brand
Senior Software Mobile Engineer, Lendable
“Justin gets really engaged with all parts of business - trying to understand every challenge and constraint, and builds really strong relationships with the other team leads in the process.”
Lorin Minxhozi
Product Lead, Not On The High Street
“Justin is a very smart, driven and full of great ideas.”
Raphael Warner
Head of Video, Future Publishings
“There is no one I would recommend more than Justin for product design. His body of work speaks for itself.”
Konstantinos Askitopoulos
Principal Product Manager, Cobalt
“Can’t believe you took the time to do this. It’s really good.”
Tweet response to my podcast on making a great product.
Konrad Kay
Co-Creator of HBO’s Industry
Growth·Design
“…a brilliant mind, with so much desire to learn and create, it was refreshing to witness first-hand.”
Louis-Xavier Lavallee
Co-Founder, Growth·Design
“Justin is one of the most considered designers I've worked with. Every decision was intentional and held to a high standard. It would be a pleasure to work with him again.”
Belen Tahir
Senior Product Designer, Depop
“Justin is an incredibly thoughtful and intelligent designer. I've been blown
away by his ability to think of new
and inventive ideas to push our
product further.”Nick Baldwin
Design Lead, Apple Podcasts
“Justin more than a designer - he is a true product partner. Someone who take lead of initiatives and helps define the strategic roadmap. With Justin, you get someone who treats your business like his own.”
Michelle De Mott
Head of Product & Data, NOTHS
Growth·Design
“Justin brings empathy, curiosity, and a rare openness to growth to everything he does. I’ve honestly rarely seen someone so eager to get better every day.”
Dan Benoni
Co-Founder, Growth·Design
Let's think through it together…
Share what you're building and where you feel its stuck.
I'll give you my take (not a pitch!)
justincampbellplatt@gmail.com
Copy my address
linkedin.com/in/justincampbellp/
Let's think through it together…
Share what you're building and where you feel its stuck.
I'll give you my take (not a pitch!)
justincampbellplatt@gmail.com
Copy my address
linkedin.com/in/justincampbellp/
Let's think through it together…
Share what you're building and where you feel its stuck. I'll give you my take!
justincampbellplatt@gmail.com
Copy my address
linkedin.com/in/justincampbellp/