Father Simon was born in 1955 in the Democratic Republic of Congo. He is the youngest of eight children, five boys and three girls. After his seminary formation he was ordained a priest for the Diocese of Mbujimayi in the Democratic Republic of Congo on June 30, 1984. During his first 12 years as a priest, he taught in a minor seminary and was the director of rural development and a parish pastor. In 1996, he came to the United States to study. He attended Denver Technical College (which became Devry University) with a degree in electronics. His assignments in the Archdiocese of Denver include:

• Saint Louis Catholic Church in Englewood
• Chaplain of the Carmelite Sisters of the Holy Spirit in Littleton
• Pastor of Cure d’Ars Catholic Church, Denver

Father Kalonga speaks French and likes movies and sports, especially soccer.