Ni-Chionna will take up her position on the board with immediate effect, and will become chair of the remuneration committee at the beginning of February.
She replaces Fabiola Arredondo, who joined the company to much fanfare in 2015. Once named the most influential woman in European business, Arredondo is stepping down from her position as chair of the remuneration committee to focus on professional commitments in the US. She will remain a non-executive director.
Ni-Chionna is currently senior independent director at two FTSE 250 companies: Royal Mail and Saga. She also holds the position of deputy chairman of the National Trust.
Burberry chair Sir John Peace said: "We are delighted to welcome Orna to the board. In addition to the experience she brings on remuneration matters, her strong UK plc and business experience will be a great asset to Burberry as we continue to focus on delivering long-term shareholder value."
Burberry also announced this morning that it had purchased almost 93,000 of its own shares from Merrill Lynch International to be held in treasury.
Shares in Burberry were up more than one per cent.
Burberry's remuneration report was the focus of some controversy last year, when a third of Burberry shareholders voted against outgoing CEO Christopher Bailey's pay.
New CEO Marco Gobbetti has laid out his vision for a more upmarket Burberry brand, but the hunt is still on to find a successor for Bailey to head up the brand's creative side.