Irish law firm Arthur Cox has appointed Geoff Moore as managing partner for the next four years.

Moore, who is currently a senior partner in the firm's corporate department, will take over from Brian O'Gorman on November 1.

Gorman will return to full-time practice as a corporate partner, having served two terms as managing partner. Firm rules specify that a managing partner can only serve up to two terms.

Moore, 44, joined Arthur Cox as a trainee in 1998, then left the firm for two years to work in the corporate finance group of a New York firm. He returned to Arthur Cox and made partner in 2007.

Moore specialises in corporate finance, private equity and equity capital markets. Moore also has an active public company advisory practice.

Moore has worked on a number of high-profile M&A cases, including Actavis's $66 billion acquisition of Allergan; Allergan's €40 billion (about $45 billion) disposal of its generics business to Teva Pharmaceuticals; Covidien's €40 billion ($45 billion) takeover by Medtronic and others in the financial services and industrial sectors.

He is also one of the firm's diversity partners, charged with helping LGBTQ staff.

Arthur Cox selects a managing partner from among its partners every four years to lead the firm.

Orla O'Connor, Arthur Cox chair, said she is delighted that Moore will become the firm's managing partner. "Geoff has risen to the very top in his professional practice and has also shown leadership within this large, busy and diverse firm," she said. "He has held several management roles in the firm, including as team leader in the corporate department and as one of our diversity partners."

Moore said he is honoured to lead the firm, which he noted has played a central role in Ireland's business life and will celebrate its 100th birthday next year. "We are facing into a period of uncertainty in the international economic and business environment, and this is a time of opportunity for the firm in ensuring that we can provide the service required by our clients operating in this changing environment," he said.

Arthur Cox is one of Ireland's largest law firms. It has more than 500 legal staff, including almost 100 partners and a total staff of more than 850. Arthur Cox has offices in Dublin, Belfast, London, New York and Silicon Valley. The firm was founded in 1920.