Dumbuya was elected as Speaker on January 21, 2014 with one hundred parliamentarians voted in his favor, and fifteen parliamentarians voted for his opponent Bu-Buakei Jabbi of the main opposition Sierra Leone People's Party (SLPP).
Dumbuya was previously the majority leader of the House of Parliament of Sierra Leone.
[8] He is an elected representative in the House of Parliament of Constituency 100 in the Freetown's neighbourhood of Kissi in the Western Area Urban District.
He was re-elected in a landslide to Parliament in the 2012 Sierra Leone Parliamentary elections with 60.65%, defeating his closest rival Sheka Kanu of the Sierra Leone People's Party (SLPP) who took 30.76%.
Dumbuya is a close ally of Sierra Leone's president Ernest Bai Koroma.