Tomoji Tanabe was born in Miyakonojo, Miyazaki Prefecture, Japan, on 18 September 1895. He began his career working as a land surveyor and civil engineer at the local city hall and later worked in the agricultural and livestock industry starting in his 40s.
He married his wife, Sugi, and the couple had five sons, and three daughters – all eight of his children were still alive at the time of his death. Sugi died in 1989 at the age of 93. When asked about the secret of his longevity, he replied: “I never drink or smoke. I drink milk every day.”
Tanabe died from heart disease in his hometown, on 19 June 2009, at the age of 113 years, 274 days. At the time of death, he had 25 grandchildren, 53 great-grandchildren, and 7 great-great-grandchildren.
In September 2005, he celebrated his 110th birthday, becoming the first male supercentenarian from Miyazaki Prefecture. His age was validated by the Gerontology Research Group on 30 October 2005.
On 12 June 2006, following the death of 111-year-old Nijiro Tokuda of Kagoshima, Japan, he became the oldest living man in Japan, at the age of 110 years, 267 days.
On 24 January 2007, following the death of 115-year-old Emiliano Mercado del Toro of Puerto Rico, he became the world’s oldest validated living man. At the age of 111 years, 128 days, he became the youngest man to hold the title since John Painter (1888–2001) over seven years prior. In June 2007, he was presented with a certificate from Guinness World Records.
On 10 April 2007, following the death of 111-year-old Kozuru Ueda, he became the oldest living person in Miyazaki Prefecture, at the age of 111 years, 204 days.