In Kenya, he played for Strathmore School, where he was also crowned Sportsman of the Year. He joined the Kenya Harlequins junior team. He was spotted by South African scouts at the 2006 Safari Sevens tournament, playing in the schools category for Strathmore School. In 2007, he joined to the Sharks academy. He progressed from Under–19 level in 2008 to Under–21 level in 2010.
He was included in the Sharks XV squad for the 2010 Vodacom Cup, but failed to play in any matches. He did play in twelve Under–21 matches later in the year and was once again included in the squad for the 2011 Vodacom Cup competition, where he made his debut in the opening match of the season, a 30–19 victory over the Blue Bulls. He made a total of ten appearances in that competition, scoring three tries. He was also included in the Sharks squad for the 2011 Currie Cup Premier Division, but failed to feature in that competition.
At the end of 2011, he was signed by the Blue Bulls. He made eight appearances for them in the 2012 Vodacom Cup, but he was then released from his contract after just six months to join New Zealand ITM Cup team Counties Manukau.
He also played for UP Tuks in the 2012 Varsity Cup, playing in three matches.
On 25 July 2013, the NFL's Indianapolis Colts announced that they signed Adongo as an outside linebacker despite the fact that he had no prior American football experience. After spending time as a member of the Colts' practice squad, Adongo was added to the Colts' active roster on 3 December 2013. Adongo appeared in two games for the Colts in 2013, but did not record a tackle.
On 7 August 2014, Adongo received a bicep injury during a pre-season game, and was waived with the injury designation by the Colts the following day. When he cleared waivers, he reverted to the Indianapolis Colts' injured reserve.
On 5 September 2015, Adongo was waived by the Colts. He was signed to the practice squad the following day. Adongo was elevated to the active roster on 12 November. He was waived again on 17 December 2015 after law enforcement personnel received at least two reports of possible domestic violence between Adongo and an unidentified female.
