He started his career in Ghana with a colts team Young Hearts, before joining Okwawu United and later Obuasi Goldfields.
At Wolfsburg, Akonnor played over 140 matches, scored over 20 goals and served as captain in the 2001–02 season before leaving the club in 2004 to join SpVgg Unterhaching.
[8] He made his competitive debut for the club on 15 August 1998, playing the full 90 minutes in a 1–0 league loss to Bayern Munich.
[13] Akonnor immediately became an important player in their team with his experience from playing in the Bundesliga, featuring in 15 of the 17 league matches in the second round of the 2003–04 season.
In Summer 2008 left Cyprus and moved to Germany based club SC Langenhagen in the Oberliga Niedersachenliga-West on a one-year contract.
[16] The team went on and placed second at the 1993 FIFA World Youth Championship, losing to Brazil by 2–1 in the final after Emmanuel Duah had put Ghana ahead in the first half.
[18] Akonnor along with players from that squad like Samuel Osei Kuffour, Mohamed Gargo, Augustine Arhinful, Emmanuel Duah and Stephen Baidoo would later graduate into the senior team to become the core members.
[19] For the senior team Akonnor would go on and make 51 international caps and later was named captain of the Black Stars following Abedi Pele's retirement.
On 19 February 2009, Akunnor signed a contract as head coach for Sekondi Wise Fighters where he worked with his former national teammate Nii Lamptey as his assistant.
[22] On 19 March 2012, Akonnor was named as head coach of the Glo Premier League club Hearts of Oak succeeding Nebojša Vučićević.
[23] In November 2012, he was sacked after a poor start of the season with the club picking four points of a possible 15 with losses in their last three games to Ebusua Dwarfs, Wa All Stars and Berekum Chelsea.
Within the season, he was adjudged the GPL NASCO Coach of March after leading Ashanti Gold to three wins and one draw in four matches within the month.
[35][36] He served for nine months, helping them to win the 2019 GFA Normalization Committee Special Competition and qualify for the 2019–20 CAF Champions League.
[41] On 30 October 2019, he was appointed as the assistant coach of the Ghana national team, serving as deputy to James Kwesi Appiah.
[48] On 13 September 2021, the Ghana Football Association announced that Akonnor along with his two assistants, David Duncan and Patrick Greveraars had been sacked after their contracts had been terminated, following an unconvincing win against Ethiopia and defeat to South Africa in a World Cup qualifying match.
[49][50] His son Charles Jesaja Herrmann is also a footballer who plays as a forward; he came through the youth system at VfL Wolfsburg.