[5] Ellemann-Jensen was born on 25 September 1973 in Hørsholm,[1] approximately 25 km (15.5 mi) north of Copenhagen.

He is the son of former Foreign Minister Uffe Ellemann-Jensen and former editor-in-chief Alice Vestergaard.

From 2000 to 2002, he worked as a legal advisor for PricewaterhouseCoopers and from 2002 to 2005 as a lawyer at IBM Denmark, where he later became head of the contract and negotiation department.

[12] In February 2023, Ellemann-Jensen announced that he would go on sick leave after having experienced stress symptoms and a brief admission to the hospital; Minister for Economic Affairs Troels Lund Poulsen acted Defence Minister in Ellemann-Jensen's absence.

[14] On 23 October 2023, he announced his resignation as party leader and his departure from Danish politics.