About Me

I am the head of the corporate/M&A team in Ireland where I specialise in advising companies and investors on mergers and acquisitions, equity fundraisings, joint ventures, shareholder arrangements and corporate reorganisations. I also support my clients with corporate governance, compliance and commercial matters.

My practice covers a broad range of industries, including the technology, aviation, life sciences, manufacturing, retail and financial services sectors and I represent companies through the full corporate life cycle, advising them on establishment, fundraising for growth and exit.

Ireland, as a gateway to Europe, continues to be an attractive location for foreign direct investment. I enjoy playing my part in helping to bring this investment to Ireland by advising clients on the establishment of operations here, either by way of acquisition or other form of strategic investment.

My primary focus is to achieve the desired result for my client. As a corporate lawyer with almost 20 years' experience, I understand that leadership, pragmatism, commercial acumen and transaction management are paramount to execute the best strategy and complete a deal on time and within budget.
My clients can rely on me to adopt a calm, common sense and good-natured approach when working with them to achieve their strategic goals and personal ambitions.

At Bird & Bird, I am fortunate to work with a global team of best-in-class lawyers who bring significant value to my clients, in particular those businesses embracing innovation and the challenge of digital transformation. Our one firm international offering allows us to develop long lasting client relationships and to provide outstanding and consistent client service on cross-border matters.
  • Advised a Nasdaq Nordic listed buyer on its entry into the Irish market by the acquisition of a leading Irish seafood business and further bolt-on acquisition.
  • Advised a global corporate services business on its entry into the Irish market by way of acquisition of a leading Irish player in this space.
  • Advised founders of educational software company on its sale to a listed Nordic buyer.
  • Advised a cloud data management company on its establishment, Series A funding and first bolt on acquisition.
  • Advised a leading helicopter lessor on a $230m joint venture with a global financial institution.
  • Advised an aircraft lessor on several joint ventures with investment funds, including a pioneering joint venture with a US pension fund.
  • Advised NYSE listed buyer on its acquisition of a leading Irish developer of high potency niche pharmaceutical products.


  • University College London – LLM in Commercial Law
  • University College Dublin - BCL


  • Law Society of England & Wales – Solicitor - 2023 (practising)
  • Law Society of Ireland – Solicitor - 2006 (practising)
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"He is a truly exceptional lawyer. His technical skills are rivalled only by his ability to communicate. He is able to drive a transaction forward and manage his team in a manner that keeps everyone motivated and focused...The service he delivers is second to none and he remains an absolute pleasure to deal with – even under extreme pressure"

2022 IFLR 1000 (32nd Edition) - Highly Regarded

"Brendan O'Brien is experienced and responsive, able to help cut through to issues that matter."

2022 Legal 500

"Brendan O'Brien is a true professional. He not only puts the client relationship at the heart of the matter, he ensures that his team deliver the best advice on time and within budget based on an agreed brief"

2021 Legal 500 - Next Generation Partner and Recommended Lawyer (Commercial, Corporate and M&A)

News & Deals

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Bird & Bird advises Evli Growth Partners

Mar 01 2024

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Bird & Bird advise Gamma Communications plc on its acquisition of Coolwave Communications

Feb 13 2024

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