[2] After completing her National Service, she worked in Private legal practice with the Law firm Ansa-Asare and Company, of Hencil Chambers in Accra, Ghana.

After serving a term in Parliament, she did not immediately contest for re-election and re-joined GAFCO as General Manager (Corporate, Administration and Legal) where she worked until December 2009.

[2] Hanna Tetteh won the Awutu Senya constituency seat in the December 2000 parliamentary election[2] and served for one term as a National Democratic Congress Member of Parliament on the opposition benches.

[9] At the 2008 presidential campaign, she played a role in managing the party's communication strategy for that election which made her a more prominent political figure and she became one of the main spokespersons for the NDC.

When John Mahama succeeded the deceased President Atta Mills in 2012, he also appointed Tetteh as the Communications Director for his 2012 election campaign.

[17][20] Following the resignation of Ghassan Salamé as head of the United Nations Support Mission in Libya (UNSMIL) in 2020, Guterres suggested Tetteh as his successor;[21][22] instead, the role went to Ján Kubiš.

[citation needed] In 2022, Guterres appointed Tetteh as his Special Envoy for the Horn of Africa, thereby switching positions with Parfait Onanga-Anyanga.