He was ordained a priest of the Diocese of Buéa on 17 April 1966, and then served as a Vicar in Soppo for a year before becoming a professor at Bishop Rogan College's seminary.

He was one of the cardinal electors who participated in the 2005 papal conclave that elected Pope Benedict XVI.

[7] In 2009, Tumi led thousands in a march in Douala to protest Cameroon's endorsement of the Maputo Protocol, a women's rights charter promoted by the African Union.

[9] In 2005, Tumi told an interviewer that the use of condoms as protection against AIDS within marriage "makes sense", though he doubted the Church's prohibition on their use would change.

[13] After a video of his corpse in the hospital bed was released on the Internet; authorities denounced it as a violation of privacy and ordered an investigation.