The International Union for Conservation of Nature said Sumatran tigers were critically endangered, and have held the status for more than 20 years.
The zoo said the exchange with Ireland was part of the European breeding programme for endangered animals.
It said every pairing was “carefully planned to maximise genetic diversity”.
Over the next six to 12 months, conservation experts would identify a genetically compatible younger female tiger to join him at Paignton.
“With habitat destruction and poaching continuing to threaten wild populations, visitors can see conservation in action and understand their role in supporting these vital efforts,” Ms Britton said.