Peter O’Callaghan, Managing Director Square Root

The value of education and finding your own path

I’ve never been able to answer the question, “Where will you be in 5 or 10 years?” Instead, I’ve leaned on a mantra that has guided a decent chunk of my career: open more doors than you close. The next move in my career has never been obvious, but this mindset has helped me embrace uncertainty and learn something new at every turn.

Growing up in a family of educators, I was grounded in the values of education, loyalty and community. Both my parents were teachers and my only sibling, my sister, became one as well. My Dad taught accountancy and finance, and eventually became Principal. My Mam initially taught Geography but then went back to study and work in Guidance Counselling and Special Educational Needs.

My parents were never ones to push us in a certain direction. I’m grateful; they gave us a strong foundation and the freedom to build our lives the way we wanted to.

School was something I genuinely enjoyed as I've always been a social person. As I tell my kids, I believe that finding your tribe – people you trust, enjoy spending time with and can rely on – is incredibly important. That sense of loyalty has stayed with me throughout my career.

I was always better at subjects like maths and business studies. I did art for the Junior Cert and I’m pretty sure I got a D! But I hadn’t a clue what I was going to do after the leaving cert or college.

Fingallians GAA team 1995

Finding my feet: “It was a stark introduction to the realities businesses face when things go wrong.”

I gravitated towards studying Accounting and Finance in DCU. I did well academically and I also really enjoyed the social element.

In 2007, during my second year of college, the Celtic Tiger was at its peak, so there was a lot of optimism in the air and that was when I agreed to join Deloitte.

Deloitte’s culture had immediately stuck out from the crowd. I had friends who were working there and loving it, so I trusted their recommendation. It didn’t hurt that at the time they offered you holiday vouchers! Deloitte also sponsored my Masters in DCU and were supportive of my decision to do it.

When I joined the Audit & Assurance practice in 2009, the world had changed. The National Asset Management Agency (NAMA) was being formed to help with the fallout from the financial crash and Anglo Irish was dominating headlines.

For me as a newcomer, this was my normal, but it was a stark introduction to the realities businesses face when things go wrong.

This period shaped my appetite for risk and resilience. I saw firsthand how companies struggled, and it built my ability to navigate uncertainty. I’m competitive, honed through years of playing sport, and that helped me through the tougher moments.

The technical knowledge I gained in Deloitte has been a game changer in my career, especially as an investor now. I can really analyse financial statements and that is invaluable.

After nearly five years, I had built great friendships and learned a tremendous amount, but I realised audit wasn't where I wanted to spend the rest of my career. Over the following years, I moved between several roles. While I didn't immediately find my long-term home, those experiences helped me understand what I valued most in a workplace: the opportunity to make a meaningful impact.

On a grad intake trip to Manchester in 2010. Organised by the late Johnny McGrath.Pictured Dan O’Connor, Myself, Harry Huston and Johnny McGrath

Creating roots and building connections: “I felt the pressure that this move had to be the right one.”

I had been working for Glanbia nutrition when I was offered a role in Bewleys, the iconic Irish hot beverage company. I felt the pressure that this move had to be the right one. My family all had secure, pensionable jobs, and were nervous about the different jobs I’d moved to.

I was optimistic. I felt I would work well with the CFO of Bewleys at the time and I thought my path would be more smooth sailing from that point.

After a few months though, he told me he was leaving.

I was faced with a decision; on the one hand, I had moved around a few times over the past few years. I had learnt a lot but I didn’t feel I could move so quickly again. On the other hand, I didn’t know who my next boss would be or how that would shape my career or experience at Bewleys.

It turned out to be one of the best things that happened in my career. I travelled to Bewley’s businesses in Boston and Sacramento, built strong relationships with the Board and family owners, and gradually, I stepped into the role of Commercial Finance Director.

It was the people as much as the opportunities that made Bewleys significant, particularly Fergal McGarry, the then COO, who later moved to Strong Roots, an Irish vegan plant-based food manufacturer.

Then came Covid-19.

Like so many businesses, we were thrown into chaos. I like to be in control, so it was difficult that so much was completely out of my hands. I learned that it’s okay to not know everything and that surrounding yourself with trusted, capable people is crucial.

The conversations I had with Paddy Campbell, the owner of Bewley’s, during this time had a lasting impression on me. His advice “Don’t sell fivers for 4.99.” is a simple phrase, but an important reminder about understanding value and having confidence in what you're offering, both in product and personally.

Although Fergal encouraged me to join him at Strong Roots, I felt a responsibility to stay with Bewley's until the business had emerged from a difficult period.

By 2022, that time had come.

Scaling a challenger brand

Joining Strong Roots as CFO felt like a natural next step.

I had long admired the brand and the founder, Sam Dennigan, had a clear vision and ambition for the business that was impossible not to be inspired by.

The company was expanding rapidly into new markets and McCain Foods had recently invested $55m for a minority stake in the business. My role was to put structure and governance on the business while ensuring we were well capitalised for the continued growth and demand in international markets.

The eventual acquisition by McCain was a significant milestone and a proud achievement for everyone involved. It was also a landmark transaction within the Irish food sector and was recognised as Agribusiness M&A Deal of the Year.

Following completion of the transaction, I knew it was time for another change.

I've always been energised by environments where I can influence outcomes, help shape strategy and contribute to growth. I had a blissful summer of playing golf, but I quickly began thinking: what’s next?

Sam Dennigan, Fergal McGarry and Myself

Building Square Root

Post acquisition, Sam wanted to establish an investment entity to support ambitious scaling founders and businesses globally. He asked me and Fergal to help him with this, each of us bringing our own different skills to the table.

We believed that the most exciting global businesses are being built by ambitious founders solving meaningful problems, and those founders often benefit most from investors who have experienced the challenges of scaling businesses themselves.

That belief became the foundation of Square Root.

Our investment philosophy is straightforward. We back businesses with strong propositions, scalable business models and leadership teams capable of creating long-term value. While financial returns are sought, we also place significant emphasis on how businesses impact people, communities and the environment.

We believe that commercial success and positive impact can coexist. That commitment led us to become a certified B Corp.

Since launching, we have invested in several businesses in Ireland and internationally. The common thread across our portfolio isn’t sector-specific; it’s businesses where doing right and doing well aren’t a trade-off.

Square Root hosting a fireside chat about Food & Technology Entrepreneurship in Lisbon

Our role extends well beyond capital. We work closely with founders on strategy, financing, supply chain development, branding and international expansion. We aim to be hands-on, constructive partners who help businesses scale while staying true to what made them successful in the first place.

I also serve as Chief Strategy Officer at Sprout &Co. It’s an incredible Irish business that is in a phase of rapid expansion. My role is helping the business continue its growth journey while preserving the culture, quality and entrepreneurial spirit that founders Jack and Theo Kirwan have built.

The power of support and balancing three kids with a busy career

Outside of work, life is busy in the best possible way.

My wife runs her own interior design business and together we're raising three children aged eight, six and one. Weekends are filled with GAA coaching, children's activities and family life.

None of it would be possible without her support.

Coaching the kids!

Looking back on my career, I wouldn’t change any of it. I’ve had sliding door moments where things didn’t go as planned, but exploring every opportunity and taking risks has been key. It goes back to my mantra, keep as many doors open as possible.

Family photo

Fergal McGarry who is mentioned in this feature passed away on May 3rd 2026. His mentorship and friendship left a lasting impact on Peter's career trajectory. His passing represents a significant loss to the Irish food and beverage sector, and to all those who had the privilege of working alongside him. He will be deeply missed.