Billy Kalonji, a committed Congolese-Belgian leader and advocate for African communities in Belgium, arrived from the Democratic Republic of Congo in the 1980s as a young student. Settling in Antwerp, he pursued studies in Human Resources at the Université Libre de Bruxelles while living with his older brother. Kalonji quickly became active in the local community, recognizing the challenges faced by African immigrants in navigating life in Belgium.

In 1993, alongside Lembé Masiala, he co-founded the association Mwinda Kitoko in Antwerp, one of the oldest still existing African associations in the port city. Initially, this organization focused on helping Congolese newcomers integrate into Belgian society while also introducing Belgians to Congolese culture. Mwinda Kitoko organized cultural activities such as African dance and culinary courses, promoting a mutual exchange of cultural knowledge.

The rise of ethnic profiling and discrimination in Antwerp during the 1990s, particularly following the successes of the far-right Vlaams Blok party, compelled Kalonji to expand his activism. In response to the growing tensions, Kalonji and other African community leaders met with the mayor of Antwerp, Léona Detiège, to address these issues. This meeting led to the formation of the African Platform (Afrikaans Platform) in 1998, a federation uniting various African associations from Francophone, Anglophone, and Lusophone countries across sub-Saharan Africa. As its president, Kalonji played a crucial role in amplifying the voices of African communities in Flanders and Brussels, advocating for their rights and integration into Belgian society.

Kalonji's activism then extended beyond local issues. He co-founded and presided over COMRAF, an association of the African diaspora in Belgium, which played a pivotal role in the renovation and decolonization of the Royal Museum for Central Africa. COMRAF's work ensured that African perspectives were included in the museum's narrative, fundamentally challenging and reshaping public opinion on Africa and its colonial history. Kalonji's efforts also included the establishment of the Collectif Mémoire Coloniale et Lutte contre les Discriminiations, a movement in an ongoing struggle to build a decolonial society, as well as Share, a migrant forum focused on promoting social justice.

Kalonji is the coordinator of Job@Ubuntu, a research and consultancy agency that works with and for the African diaspora in Belgium. His work continues to emphasize cultural diversity, youth engagement, and the ongoing struggle against racial injustice.