He is a member of Parliament for Dagoretti South Constituency in Nairobi County under the United Democratic Alliance.
Before entering politics, he was a journalist at Nation Media Group and a Director for Redykulass Limited.
He left Nation Media Group to join Ogilvy Africa as an art director in 2008.
Kiarie was elected as the member of parliament for Dagoretti South in 2017 under the Jubilee Party of Kenya, where he finished first[7] ahead of five other candidates.
He voted yes on the 2024 finance bill, against public opinion, and later stated that the Kenyan #rejectfinacebill2024 demos were "fake edited photos".