Countertenor Keith Pun was born and raised in Hong Kong. Prior to pursuing his postgraduate vocal studies at the Royal College of Music, he read music at the Chinese University of Hong Kong. In 2016, he completed his Opera Works training at the English National Opera.

Keith Pun is a versatile countertenor who is particularly interested in collaborating with composers to create new works. For Leeds Opera Festival in 2018, he played Chai Ping in Raymond Yiu's The Original Chinese Conjuror. Additionally, he gave solo performances for Duyun's opera Angel's Bone, winner of the Pulitzer Prize, at the Beijing and Hong Kong Music Festivals. He took part in the 2019 world premiere of Elena Langer's Beauty and Sadness, which was conducted by Gergely Madaras. He played the roles of Fish and King in Alex Ho's new anti-opera Untold, which won the George Butterworth Prize. In 2022-23 season, Keith Pun made his Longborough Opera festival debut in a double bill of Freya Waley-Cohen's Spell Book and Francesca Caccini's La liberazione di Ruggiero. He was a resident artist at Britten Pears Arts for Untold, and toured the UK with English Touring Opera in the title role in Tutankhamun's Shoes. Keith Pun also made his Linbury Theatre debut in Ruination at the Royal Opera House.

Frequently in demand on the recital and concert platforms, Keith Pun has appeared at the National Gallery and St John Smith Square in the United Kingdom, Germany, Austria, Hong Kong and Japan. He has performed as a soloist under the baton of John Butt, Jonathan Cohen and Matthew Halls. Keith Pun has worked in masterclasses with Gemma Bertagnolli, Michael Chance, Dietrich Henschel, Charlotte Margiono and Deborah York. He was a Nieuwe Stemmen Artist at Operadagen Rotterdam and New Generation Artist at Iford Arts Festival.