[2] His debut in Serbian SuperLiga was on 14 March 2010, when he came in as substitute against FK Čukarički, and he scored his first goal just seven days later in a match against Mladi Radnik.

While on loan at Vojvodina, in 2012 after one game with Spartak Subotica, he fell very ill and was admitted to the hospital, where he was diagnosed with thrombocytopenia.

He is a little angry..." On 31 August 2014, in a last-minute deal before the transfer window closed, Katai devoted to a one-year loan to Red Star Belgrade.

By the end of October 2015, Katai had scored 10 goals and made 6 assists in 15 league matches, ranking him one of the most effective midfielders in all of Europe at the time surveyed.

[12] In the first game of the third round of qualification for the Champions League against Bulgarian PFC Ludogorets Razgrad, Katai continued his goal-scoring series with a 12th consecutive goal, when he dribbled past three players and scored.

On 31 August 2016, Katai signed a three-year contract with La Liga side Deportivo Alavés, for an undisclosed fee.

[16] On 31 December 2019, after leaving the Chicago Fire, Katai joined the LA Galaxy through the use of Targeted Allocation Money.

[19][20] Katai's wife, writing in Serbian, had compared protestors to "disgusting cattle", called for violent action against them in a caption under a photo of New York Police Department officers driving an SUV into a crowd of protesters ("shoot those s***s"), and captioned an image of what appears to be a looter running off with boxes of Nike sneakers with "Black Nikes Matter".

[29] He earned a total of 10 caps (no goals) and his final international was a November 2020 European Championship qualification match against Scotland.