The Associated Press reported that Acellam was captured along with two other rebel fighters after a brief tussle near the Congo-Central African Republic border.
Ugandan officials said Acellam was one of Kony's top military strategists, though he was not of the commanders indicted by the International Criminal Court in 2005 along with Kony.
Lt. Col. Abdul Rugumayo said Ugandan forces found 30 rebels in total, but only Acellam and two other rebel fighters were captured. Ugandan forces staked out Acellam's camp for three weeks after tracking them, reported the AFP.
Acellam apparently split away from a larger group of LRA fighters after a possible fight. Acellam only had an Ak-47 rifle and eight rounds of ammunition with him when he was found. He was accompanied by his wife and daughter, reported the Christian Science Monitor.
Rugumayo said Acellam was in good condition following the capture.
Acellam was flown to a South Sudanese base for regional forces currently hunting down the LRA.
My coming out will have a big impact for the people still in the bush to come out and end this war soon, Acellam said to the AFP. He was flown to the South Sudanese base for medical checkups.
While speaking, Acellam referred to himself in the third person, saying the general of the division, Caesar Acellam, who has fought in the jungle since 1984, is from now on in the hands of the Ugandan Army, he said to the AFP.
A Ugandan army official, speaking anonymously to the Associated Press, said Acellam's capture would hurt Kony, whose forces have already been weakened from lack of food and the constant moving to elude capture.
He is big fish, very big fish, said the official about Acellam to the Associated Press. He is one of the top division commanders.
Kony, leader of the LRA, has eluded capture. Ugandan officials believe he is hiding in Sudan. The leader prefers to live away from his top commanders as a security precaution.
Kony does not want his commanders near him, an official said to the Associated Press. He wants to be alone.
An analyst has called Acellam's capture an intelligence coup.
The abuses at the hand of Kony were recently brought to light after U.S. non-profit organization Invisible Children released an online documentary film entitled 'Kony 2012' that highlighted the atrocities of the LRA. The video was viewed on YouTube more than 100 million times.
President Obama sent 100 troops to help regional forces hunt down LRA members. Rebels have easily evaded capture by moving in small groups and avoiding using technology. The U.S.-African Union backed coalition has been tracking Kony through Uganda, Central African Republic, South Sudan and the Democratic Republic of Congo.
Acellam is considered to be the LRA's fourth-highest ranking member. He has been with the group for over 20 years.
The LRA's top three commanders, Okot Odhiambo, Dominic Ongwen and Kony, are still at large. They are wanted by the International Criminal Court, who charged Kony, along with others, in 2005 for war crimes, including rape, murder of civilians, mutilation, and forcing children to serve as soldiers and sex slaves.
The ICC's chief prosecutor Luis Moreno-Ocampo said last week that Kony would be captured or killed this year, reported the AFP. A day later, reports came out saying Kony may now be hiding out in Darfur.