Before serving as a priest, he was a teacher at the government school at KGVI and at the Selwyn College of the Church of Melanesia.

Vunagi later moved to Canada, where he was assistant priest at St. Anselm's Parish in the Diocese of New Westminster, British Columbia, from 1996 to 1998.

[4] He was elected the 5th Archbishop and Primate of the Church of the Province of Melanesia on 4 March 2009, in a Provincial electoral board, held in Honiara, being enthroned on 31 May 2009.

[7] Archbishop Vunagi left office on 6 September 2015, in a ceremony that took place at St. Barnabas Cathedral, in Honiara, attended by the nine bishops of the Anglican Church of Melanesia.

In June 2019, he was the sole candidate to become the next Governor-General of Solomon Islands, the monarch's viceregal representative in the country, and officially took office on 7 July 2019 (Independence Day).