Ambongo served as a parish priest and as a professor before his episcopal career and since becoming a bishop has been a leading voice among his conferees for national peace.

Fridolin Ambongo Besungu was born in Boto on 24 January 1960 and prepared for the priesthood by studying philosophy in Bwamanda and theology from 1984 to 1988 at the Saint Eugène de Mazenod Institute.

[5] He received his episcopal consecration on 6 March 2005 from Joseph Kumuondala Mbimba with the co-consecrators Giovanni d'Aniello and Cardinal Frédéric Etsou-Nzabi-Bamungwabi in an open-air Mass in front of the Bokungu Cathedral.

Ambongo later led a mission of bishops to Lusaka, Zambia, to meet with Zambian President Edgar Lungu to urge him to support holding peaceful elections in the D.R.C.

In their message to Lungu, the bishops urged support for a "credible, transparent, inclusive and peaceful election" to solve "the socio-political crisis" plaguing the nation.

[2] On 30 May 2018, Ambongo issued a statement in Mbdanka-Bikoro announcing that there would be a suspension of those sacraments that require physical contact to administer due to an outbreak of Ebola in the area.

[9] Ambongo condemns the exploitation of natural resources and believes that renewables will help alleviate the impact of climate change in the world.

Ambongo also collaborated with Cardinal Christoph Schönborn to secure a meeting between the German and Congo environmental ministers to discuss what the countries could do to improve the quality of the environment in their respective nations.

[11] On 6 February 2018, Pope Francis appointed Ambongo the coadjutor for the Kinshasa archdiocese,[11] to succeed Cardinal Laurent Monsengwo Pasinya upon his resignation.

[19] In April 2024, the prosecutor general of the Court of Cassation ordered the opening of a judicial investigation against Fridolin Ambongo Besungu.

Fridolin Ambongo Besungu is accused of seditious remarks constituting "false rumors, inciting populations to revolt and attacks against human lives".