In June 1983 Colonel John Garang de Mabior joined a mutiny of the garrison of Bor, forming the SPLA in October 1983. Bol, then a lieutenant-colonel in the army, sent several of his wives and children to safety in Nairobi, Kenya, and joined the SPLA as a field commander, along with William Nyuon Bany. Garang was the Commander-in-Chief, Bol second in command, Bany third and Salva Kiir fourth. Bany was also the Chief of Staff, In 1986 Bol was deputy commander-in-chief of the SPLA and deputy chairman of the SPLM provisional executive committee. In 1987 he led a successful attack on several towns in Blue Nile province to the north of South Sudan. Growing over-ambitious, he was accused of plotting a coup against Garang and was jailed for the next six years.
SSIM commander
In August 1991 Riek Machar, Lam Akol and Gordon Kong announced that Garang had been ejected from the SPLM. They formed a rival militia called the SPLA-Nasir, after their base in the town of Nasir. On 5 April 1993, at a press conference in Nairobi, three rebel factions – including SPLA-Nasir ) – announced a coalition, to be called "Sudanese People's Liberation Army-United", known as SPLA-United. It included a number of former Garang officials and other southerners. Bol's Dinka forces made an important addition to the formerly Nuer-dominated SPLA-Nasir. Bol became deputy Commander in Chief. Although seeking independence for South Sudan, the group received covert support from the Government of Sudan as it fought the SPLA between 1991 and 1999 in attacks that became increasingly violent and ethnically motivated.
Government ally
Early in 1995 Machar dismissed Bol and Bany from his South Sudan Independence Movement on the basis that they had signed military and political agreements with the government of Sudan late in the previous year, and that they had attempted to form a government-supported faction in the SSIM. The Sudan government tried to make Bol a leader in his home province, but he was not successful in gaining support of the local Dinka, and members of his militia returned to their villages. In January 1998 Bol's forces briefly seized Wau, the main town in Bahr al Ghazal. From this strong position, he applied to rejoin the SPLA. He was accepted, but assigned to a headquarters position rather than a field appointment. In disgust, he returned to the Sudan Government and in 1999 joined the South Sudan United Army, a militia headed by Paulino Matip.
Death
Later in 1999, Commander Peter Gadet fell out with Paulino Matip. During the struggles that followed, Bol was shot in obscure circumstances on 10 September 1999. He left several wives and more than 20 children.