Dimitris Giannoulis became the first Greek player to sign for Norwich when he joined Norwich on 19th January 2021 on loan from PAOK Salonika. The deal includes a permanent move for an undisclosed fee in place if the Championship leaders seal promotion back to the Premier League - believed to be £6.2million.

He travelled to Norwich on 15th January and spent the weekend having medicals and finalising terms. Giannoulis, who will wear the number 30 shirt, was the man identified by Stuart Webber’s recruitment department as a Premier League grade option, as City look to find a longer term successor to Jamal Lewis. 

Giannoulis was spotted by PAOK's scout Giorgos Kostikos aged 18 whilst playing for Vataniakos FC in the fourth tier of Greek football. He completed his move to the Super League side for a fee of €20k on a salary of €850 euros a week. He had played just 34 games for Vataniakos. Despite his talent never being questioned, his performances were lacking. Giannoulis struggled to make his opportunities count and was sent out on loan to fourth-tier side Pierikos in 2014. Giannoulis was deployed a left-winger and discovered some form, making 28 appearances and catching the eye with exceptional performances. That earned him a loan move to the Super League, the top-flight in Greece, with Veria. 

Under former Newcastle United winger Giorgos Georgiadis, he played regularly in the top-flight, helping the club survive in the league. He made 26 appearances. His performances saw him crowned 'Young Player of the Year' and didn't go unnoticed by his parent club . PAOK brought him back into the first-team group with the intention of Giannoulis having his breakthrough season. Instead, the coaching staff and sporting director didn't trust his talent, and a loan move to Cyprus with Anorthosis followed. It proved to be short-lived with Dimitris making just eight appearances.

He then joined Atromitos on a two year loan deal. "When I went to Atromitos, I was affected (by the failed loans) and everything seemed like a mountain to me. I had fallen because of the loans, because of my poor performance. When I went to Atromitos, I said that here I will build my career, here I will show what I am worth. It was the period when I was thinking only of myself." There was a raw determination that underpinned his efforts to get into PAOK's senior team. After two seasons, 56 games and 14 assists, his opportunity arrived. 

A training camp in Holland really pushed Giannoulis on. PAOK were in the market for a new left-back, but his performances during that pre-season camp persuaded the club to give him a chance. Since being handed his first appearance for the club, Giannoulis has improved drastically. Giannoulis is now a regular for his country, ahead of Liverpool's Kostas Tsimiskas, someone he has been compared to relentlessly since his emergence at PAOK. The 25-year-old Greece international has been linked with moves away from PAOK consistently for the last season, but despite interest from Porto, Atalanta, Newcastle and Rennes, it is the Canaries have convinced Giannoulis to leave his native country. He had played 74 games for PAOK at the time of his loan, scoring twice. He won the Greek Super League in 2018/19 along wih the Greek Cup. He has played in the Champions League and Europa League.

He made his international debut on 15th May 2018 against Saudi Arabia in a 2-0 defeat that saw him sent-off on 43 minutes.

He said "I’m really happy to have signed. It was a dream to play for an English team and now that has come true. It’s been a busy few days, but I’m here and I can’t wait to get on the pitch with my new team mates. I will always give my best. I consider myself a fast player, both in attack and defence. I like Norwich’s style of football and I hope I adapt to the way that the team plays and that I can help the team get promoted.”

Dimitris made his Norwich debut in the 0-0 draw with Middlesbrough on 30th January 2021. He went on to make 16 appearances as the Canaries won the Championship title. This activated a clause in the contract which saw Dimitris transfer permanently to Norwich. He formally completed his move to Norwich on 1st July 2021.

On 12th September 2021 it was reported that Norwich rejected a £13million bid from Roma during the Summer 2021 transfer window. Reports in his native Greece on Sunday claimed Jose Mourinho's club targeted Giannoulis on a list of potential replacements for Italy's injured Euro2020 star Leonardo Spinazzola.

At the end of February 2022, Giannoulis was reported to be interesting Atalanta and Real Sociedad according to reports from Greece. He had made just 11 appearances at the time of the report, having fallen behind Brandon Williams in the pecking order and so reportedly would be interested in a loan move away from Carrow Road.

He made 22 appearances in 2021/22 as Norwich finished bottom of the Premier League.

He made 27 appearances for Norwich during the 2022/23 season. On 18th May 2023 reports from Greece suggested that Greek giants Panathinaikos are monitoring Giannoulis ahead of a potential summer swoop. The Greens are in the market for a left-back, according to a report from Sport24, and have been surveying Giannoulis' situation as his future hangs in the balance at Carrow Road. The 27-year-old only has one year left on the contract he signed in 2021, and has also been the subject of interest from Russian sides CSKA Moscow and Dynamo Moscow.

In January 2024 there was speculation in Greece that Ajax were keen to sign Giannoulis but he remained in Norfolk with contract talks due to commence.

He made a total of 38 appearances in 2023/24 as Norwich finished sixth reaching the Championship play-offs, before losing 4-0 to Leeds. On 20th May 2024 it was reported by Norwich that Dimi would be leaving the club on expiry of his contract that summer. He had played 103 games for City.

On 18th June 2024 Sky Sports Germany’s Florian Plettenberg reported FC Augsburg – who finished 11th in the German top flight last season – have edged ahead of clubs in England, Italy and Greece to sign Dimi. AEK Athens, along with Panathinaikos had been linked. Dimi eventually signed a four year contract with Augsburg on 23rd July 2024.

Dimitris' brother, Kostas, is also a professional footballer who at the time of the transfer played for OFI in the Greek Super League