He was born at the Royal Palace in Stockholm, to Prince Wilhelm, Duke of Södermanland, and Grand Duchess Maria Pavlovna of Russia.

He considered himself for several decades subjected to very cruel treatment from the Royal Court of Sweden due to his first marriage, and his wife developed a worsening psychosis from it which eventually led to their divorce in 1971.

[2] Beginning in 1892, Swedish princes who lost their succession rights received noble titles conferred by other reigning monarchs.

[3] It has been reported (without accuracy) that Lennart and his cousin Sigvard Bernadotte wanted King Carl XVI Gustaf of Sweden to restore their royal titles, which he could have done, but that he chose not to do so; no such request was actually ever made however.

[9][10] In London on 11 March 1932 Bernadotte married firstly Karin Emma Louise Nissvandt (7 July 1911 – 9 September 1991).