The younger brother of Abdullah Öcalan, Osman studied at teachers' training college before joining the PKK when it was founded in 1978 and spent two years in Libya.

[5] In 2000 The Independent referred to him as a "senior commander" of the PKK when Medya TV, the underground Kurdish satellite television channel reported him as claiming that the Turkish authorities wanted his brother to die.

[6] In March 2003, in an interview with western journalists from his refuge in the Qandil mountains, he asserted "We will never allow ourselves to be disarmed as long as the Kurdish issue is not settled".

[7] He split away from the PKK again in August 2004 to form the Patriotic Democratic Party (Kurdish: Partîya Welatparêzên Demokratên; PWD) with Hikmet Fidan, after a lost power struggle with Murat Karayılan and Cemal Bayık.

[10] Speaking from his home in Koya in Iraqi Kurdistan, he claimed that Turkey was denying medical treatment to his brother Abdullah Ocalan and warned that suicide bombers would strike Turkish cities if he died in prison.

[13] In August 2009, Hurriyet reported that Abdullah Öcalan had produced a 125-page petition in which he suggested that his brother Osman be investigated for his links to Ergenekon.

[15] It was thought by the public and some news organizations that Öcalan was wanted with a red notice at the time of the TRT Kurdî's interview.

[16] Recep Tayyip Erdoğan, President of the Republic of Turkey, made a statement regarding the interview as "I don't know that Osman Öcalan is wanted with a red notice.