[5] David Duncan began his club career at Afienya United in 1984 before moving to Premier Division side Great Olympics two years later.
The Black Starlets had a poor showing in the FIFA Under-17 World Cup in Peru where they were eliminated in the first round, in the midst of public disagreements with GFA administrators.
In that short period of time, he led Free State Stars to victory in the Phakisa[13] Cup in 2009 beating Soweto giants Orlando Pirates and Chiefs.
The Ghanaian coach left Free State Stars in August 2008 after they appointed Owen Da Gama as Technical Director of the club.
It was a case of deja vu for David Duncan's Ashgold the following season when they placed second with 53 points and lost the league title to Berekum Chelsea.
The poor form pushed Hearts of Oak into the relegation mire in the latter stages of the first round of the 2012–13 Glo Premier League season.
[20] The new Accra Hearts of Oak manager won his first trophy for the Continental Club Masters in the 2013 GHALCA President's Cup competition.
He led his team, Hearts of Oak, to a 4–3 penalty win over Congolese giants TP Mazembe in the first day of the competition to progress to the finals of the President's Cup.
However, he lost the second game of the season[23] to bitter rivals Kumasi Asante Kotoko 0–1 at the Accra Sports Stadium after losing his key players, notably, Edubiase two-goal hero Emmanuel Hayford to injury, team captain Moro Abubakr to suspension, and a few others.
His young side dominated the exchanges, missing countless glorious chances, but Kotoko snatched the points through a Seidu Bancey beauty in the 29th minute.
Duncan's side put the disappointment of the derby defeat aside, and went on to win their next four games, beating new entrants Inter Allies[24] 2–3, Sekondi Hasaacas[25] 2–1, Bechem United[26] 0–1, and Berekum Chelsea[27] 1–0.
They dropped points at the Kpando Park after taking a first half lead through Emmanuel Hayford, but Heart of Lions fought back to snatch a 1–1[28] draw.
[32] They organised a peaceful demonstration, led by supporters' leaders, Barima Atuahene, Maxwell Asabere, and members of the radical Chapter O group, to reinstate David Duncan as the coach of the club.
The new group, opposing the sacking of David Duncan, succeeded in moving the coach back to the residential camp[33] of the club ahead of a big game against Amidaus Professionals.
After successfully weighing both sides of the case, the Ghana Football Association authorized Hearts of Oak to pay a record $40,000 as compensation to David Duncan for wrongful dismissal.
Kotoko were struggling in the season having accumulated 10 points from 10 games and lying precariously on 14th position on the Ghana Premier League log.
Duncan also led Kotoko to the finals of the 2015 Ghanaian FA Cup where they lost under controversial circumstances to Medeama Sporting Club.