"I was informed that a member of al-Shabab contacted our forces in the front line of Barsanguni requesting to surrender to the government forces and they cooperated with him," said Mohamed Hassan Badal, commander of Unit 11 Section 43 of Juba land forces.
He told journalists that Sidow Abdi Gedi, surrendered in Kismayo, in Somalia's southern region of Lower Juba.
The former al-Shabab leader who spoke to the journalists said he joined government forces at his willing.
"I have been serving with al-Shabab for seven years but I am now in Kismayo with the government forces," Gedi said.
This move came two weeks after five al-Shabab extremists surrendered to government forces in Gedo, in southern Somalia.
Meanwhile, two soldiers, including a military commander, were killed and six others injured by a roadside bomb on Saturday evening in Bardale district of Bay region, southwest Somalia.
Al-Shabab was ousted from the capital Mogadishu in 2011 but the terror group is still capable of conducting attacks, targeting government installations, hotels, restaurants and public places.