Donis was born and raised in Frankfurt, West Germany until he was six years old and the family moved back to their native Greece.
On 5 June 1996, after helping the Greek club reach the UEFA Champions League semi-finals against Ajax, Donis moved to Blackburn Rovers on a free transfer, making use of the then recent Bosman ruling signing for 1.1 billion drachmas, a record amount for Greek players at the time.
He then made the move to AEL where, after one season, he managed to bring the team to the Greek Superleague from the second division, and reached eighth place the following year.
In 2007, Larissa finished only tenth in the league, but he managed to win the Greek Cup after defeating Panathinaikos 2–1 in the final.
[8] On 17 November 2008, due to a string of poor performances and early knock out from the UEFA Cup, AEK parted company with him just six months after his appointment.
[9] In 2009, Donis was appointed by Atromitos and in the 2010–11 season he again reached the Greek Cup Final only to lose 0–3 to his former team AEK Athens.
[10] On 28 April 2013, after a crucial defeat 0–2 and the elimination in the semi-final of Greek Cup by Asteras Tripolis, he was sacked by chairman Ivan Savvidis.
[19] Donis led his team to some great performances in the group stage, but APOEL managed to collect only one point after drawing 1–1 with Ajax at home.
On 6 January 2015, APOEL and Giorgos Donis parted company by mutual agreement after a poor run of performances and results, culminating in a 1–1 home draw against the last-placed Ayia Napa.
[26] On 19 July 2020, after the end of the Superleague playoffs, he left the club by mutual consent, mainly as a result of his strenuous relationship with the Panathinaikos board and chairman Giannis Alafouzos.