John Evans was born in Swansea, Wales, UK, on 19 August 1877. He started working in the mines at the age of 13.
In 1902, he married Alice Horne. The couple had three sons and one daughter.
At the age of 108, he became the oldest person to a pacemaker implanted. The operation was performed at the University Hospital of Wales in Cardiff. He returned home just three days after later. When asked about the secret of his longevity, he said: “No alcohol, no tobacco, no cursing, and no gambling.” He visited London for the first time on his 110th birthday.
Evans died at his house in his hometown, on 10 June 1990, surrounded by his family. He was 112 years, 295 days old.
On 19 August 1877, following the death of 107-year-old Alfred Grant of Dovercourt, England, he became the oldest living man in the United Kingdom, at the age of 106.
On 5 January 1987, following the death of 111-year-old Herman Smith-Johannsen of Norway, he became the oldest living man in Europe, at the age of 109.
On 25 November 1988, following the death of 112-year-old Alphaeus Philemon Cole of the USA, he became the world’s oldest living man, at the age of 111 years, 98 days.
On 27 May 1989, at the age of 111 years, 281 day, he surpassed the final age of John Mosley Turner (1856–1968), becoming the oldest the oldest British man ever. He held the record for almost 20 years, until 29 March 2009, when Henry Allingham surpassed Adams’ final age.