German midfielder and former Budesliga winner Moritz Leitner joined Norwich City on loan from Augsberg on 25th January 2018 until the end of the 2017/18 season. He made his debut as substitute against Brentford on 27th January 2018.

Leitner started his football career at FC Unterföhringsince joining them when he was two. When he was six years old, he moved to 1860 München, where he started his career. He made his professional debut on 14th August 2010 and set up the equaliser in a game 1860 eventually won. He made 18 appearances before moving to Borussia Dortmund in January 2011.

He signed a four year contract with Dortmund and was then loaned to Augsberg until the end of the 2010/11 season, ,making 9 appearances. Returning to Dortmund, he played 22 games in his first season as they won the Bundesliga. The following season saw him help Dortmund to the Champions League final although he was on the bench for the final against Bayern Munich. He played a total of 66 games for Dortmund.

On 1st July 2013, Moritz Leitner joined VfB Stuttgart on loan until June 2015. Leitner finished his first season at Stuttgart, making twenty-four appearances and scoring once in all competitions. During the second season he fell out with the manager and made just 20 appearances, scoring once.

On 12th August 2016, Lazio signed Leitner from Borussia Dortmund for a fee of €1.5 million. He made just two appearances due to injury and the form of his rivals.

On 31st January 2017, Leitner signed for Bundesliga side Augsburg signing a four-year deal for a reported fee of €2 million. He made six appearances in the 2016/17 season and no appearances in 2017/18.

Leitner was capped by Austria at Under-17 level due to his mother's nationality, playing against Estonia in May 2008. After receiving German citizenship in September 2010, he made his debut for the German Under-19 side against Denmark. He scored a total of seven goals for the Under-19s. He made his Under-21 debut against Cyprus on 9th August 2011 and scored his first Under-21 goal against San Marino on 10th October 2011. He later captained the Under-21s.

Leitner made 12 appearances whilst on loan to Norwich. Impressing, he signed a four year deal with Norwich on 26th June 2018 for an undisclosed fee. “I feel very happy to be here,” said Leitner. “When I arrived here on loan, to be honest I came here because of (head coach) Daniel Farke and (sporting director) Stuart Webber. I had an unlucky situation at Augsburg and the whole family of the Canaries, the supporters, everyone in the dressing room and in training helped me so much and gave me a good feeling. So for me it was clear if I got the chance I would come back and help the club to get success .I just want to be a part of this club and for sure I’m really happy and also really proud to be here and to wear the shirt"

Daniel Farke added Farke added: “I’ve made it clear that Mo is an outstanding player with unbelievable technical ability. He’s had two and a half difficult years that meant we could get him here for a loan spell, and you could see how important he can be and what a great footballer he is. It’s outstanding to have him here on a permanent signing, and I’m really looking forward to having him in the squad. It will be good for him to have a whole pre-season with us. I think there’s even more of him to come, and to step back on to the level he promised in his younger years."

Leitner scored his first goal for Norwich in the East Anglian Derby at Ipswich on 2nd September 2018 which finished 1-1. Mo finished the season with 31 appearances and two goals due to injury in the latter half of the campaign. However his contribution helped Norwich win the Championship title and promotion to the Premier League.

Leitner made just 10 appearances in Norwich's ill-fated 2019/20 Premier League campaign. He fell out of favour and didn't play during the 2020/21 season. He departed Norwich by mutual consent on 29th June 2021.

On 1st August 2021 it was reported by Polish sports newspaper Przeglad Sportowy that Leitner was training with Polish champions Legia Warsaw. This follows a serious knee injury for Poland international Bartosz Kapustka after scoring during Champions League qualification last month.Legia are preparing for the first leg of their third-round tie against Dinamo Zagreb on Wednesday and it seems Leitner is the player they see as a potential replacement. It later emerged the Greman midfielder had actually been training with Rakow Czestochowa, who were runners-up behind Warsaw in 2020/21. Reports suggested that Rakow weren't convinced by the 28-year-old's fitness though, having not made a first-team appearance since January 2020.

On 7th August 2021 he signed for Swiss side FC Zurich on a one year deal. Zurich finished eighth in the Swiss top lfight in 2020/21 and narrowly missed relegation. Sporting director Marinko Jurendic told his club's website: "Moritz Leitner has a high level of game intelligence and wants to take on responsibility on the pitch."

Leitner left FC Zurich after one season.