Ms O’Neill will succeed Roger McMillan as managing partner and Mr Magee will succeed Neasa Quigley as senior partner with effect from 1 May 2026.

During Mr McMillan and Ms Quigley’s six-year term, the firm saw its turnover grow by 48 per cent from £15 million to £23 million and its headcount increase from 170 to 230 across its Belfast and Dublin offices, including 136 lawyers and 46 partners.

Ms O’Neill, who joined Carson McDowell as a trainee in 1998, has built a distinguished career at the firm, most recently serving as partner and head of the employment team for over 10 years.

As managing partner, she will lead the firm’s operational management, people development, financial performance and internal systems.

Commenting on her appointment, Ms O’Neill said: “I am delighted to have been appointed by my partners to lead Carson McDowell during its next period of growth and development.

“The firm has grown significantly in terms of people, turnover and reputation under Roger and Neasa’s leadership. I congratulate and thank them for their outstanding vision and progress made.

“I am honoured and committed to driving the firm forward, further strengthening our internal capabilities, embracing innovation and supporting our people.”

Mr Magee joined the firm in 1995 and has led the litigation and dispute resolution team for more than 15 years.

He will oversee the firm’s strategic direction and external engagement with clients, stakeholders and the wider business community.

He said: “I am honoured to take on the role of senior partner at such an exciting time for Carson McDowell.

“I look forward to working closely with Orlagh and the wider team as we continue to build on the firm’s strong foundations, deepen our client relationships, champion the values that have made the firm successful and drive forward our strategic ambitions.”

In a joint statement, Mr McMillan and Ms Quigley said: “When we took on the roles of managing partner and senior partner in 2019, the leadership of Carson McDowell was shared between us.

“This approach has served the firm exceptionally well, allowing us to combine our strengths and guide Carson McDowell through a period of strong and sustained growth.

“We are immensely proud of the culture, capability and reputation that has continued to develop across the firm, the dedication shown by our colleagues and the loyalty and support of our clients.”

They continued: “It has been a privilege to lead the firm during such a transformative period and are delighted that Orlagh and Declan will now take on these roles.

“Meanwhile, we look forward to continuing to contribute to the firm in our ongoing practice roles and to supporting the next chapter of its development.”

Mr McMillan will continue in his role as head of healthcare, and Ms Quigley will remain as joint head of corporate and head of energy and renewables.