The 29-year-old, who has captained the Highlanders in the Super 14, will arrive at Sandy Park in November upon the conclusion of Hawke's Bay participation in the ITM Cup.
A former New Zealand Colts captain, Shoemark also played Super Rugby for the Blues.
"Jason could easily be regarded as one of the best midfield players not to be capped by the All Blacks," said Exeter head coach Rob Baxter.
"He will bring leadership and competitive qualities to our team that will be vital in the Premiership.
"He is currently at the top of his game having played a full part in the Super 14 with the Highlanders this year and earning a call-up to the All Blacks squad last season."