Tammet was born Daniel Paul Corney[5] and raised in Barking, East London, England, as the eldest of nine children. He suffered epileptic seizures as a young child, which he subsequently outgrew following medical treatment.
He participated twice in the World Memory Championships in London under his birth name, placing 12th in 1999 and 4th in 2000.[5][6]
He changed his birth name by deed poll because "it didn't fit with the way he saw himself." He took the word Tammet from the Estonian for 'oak tree'.[7]