His father was Philipp von Boeselager, an officer in the Wehrmacht who took part in the 20 July plot to assassinate Adolf Hitler in 1944.

From 1968 to 1970, following in the footsteps of much of the Boeselager family, he served in the military and retired as a Lieutenant of the reserve forces of West Germany.

Boeselager was dismissed from his positions and expelled from the Order of Malta by Grand Master, Matthew Festing for alleged involvement in distributing condoms (considered "instrinsically evil" in Catholic teachings) in Myanmar through the Malteser International.

According to media reports, Festing and Cardinal Patron of the Order of Malta, Raymond Leo Burke, demanded Boeselager's resignation, which he refused, whereupon Festing declared him deposed and provisionally expelled from the Order of Malta; the main reason cited was for the distribution of condoms by Malteser in Myanmar.

[6][7] Boeselager appealed against his removal to Pope Francis, who appointed a five-member commission of inquiry of the State Secretariat under Cardinal Pietro Parolin to investigate.

[10][11] The UK-based liberal Catholic magazine The Tablet interpreted the dispute as evidence of a power struggle between Cardinal Raymond Burke and Pope Francis.

[9] On 25 January 2017, the Holy See Press Office announced that Grand Master Festing had submitted his resignation during an audience with Pope Francis.

[12] At its meeting of 28 January 2017, the Sovereign Council of the Order of Malta accepted Festing's resignation and the reinstatement of Boeselager.

indicated that the row was a pretext, that Cardinal Burke wanted the knights to promote his traditionalist vision of Catholicism and that when von Boeselager was sacked he had told friends that he had been labelled as a "a liberal Catholic".