In 1974, General Uulenga, also referred to as "Hollo," joined the liberation war and left the nation.

After receiving PLAN Infantry training at Angola's Cassaba Base, he was sent to Cunene Province where he fought at the front both inside and near Namibia's borders.

After moving up the ranks, he was promoted to Brigadier General, a position he retained until his retirement from active duty in 2015.

He held a number of posts in the NDF military during his tenure, including, General Officer Commanding 26 Motorized Infantry Brigade, Deputy Commander of the 21 Motorized Infantry Brigade, SSO Security Intelligence, SSO CounterIntelligence at the Defence Headquarters (DHQ).

He Also served as the Eastern Front Chief of Staff during Operation Atlantic in the Democratic Republic of the Congo.