During his career he played for HC Dinamo București and KC Veszprém and he was also a member of the Romanian national handball team.

At the time of his death, Cozma was allegedly in talks with several major handball clubs in Spain, including FC Barcelona.

The members of KC Veszprém were celebrating the birth of the son of a player and the birthday of another, when they got into an altercation with a gang of 25-30 Romani people.

Then a few hours later the convoy entered Romania and went through Nădlac, Arad, Deva, Sibiu, Braşov and Ploieşti to the applause of tens of thousands of people all the way along, before arriving to Bucharest after an 18-hour long journey.

[5] The Romanian Handball Federation Board decided that the Olympic National Center of Excellence in Sighişoara will change name to Marian Cozma.

[6] The Handball Federations of Romania and Hungary have agreed to organize an annual commemoration match between the national teams of the two countries in the memory of him, both in Veszprém and Bucharest.

[citation needed] The City Hall of Bucharest Sector 2 decided to give the "Distinction of honor" to Marian Cozma post-mortem.

[10] KC Veszprém played its first match after Cozma's death on 15 February, against Ademar León in the EHF Champions League.

The Veszprém players entered the court for team presentations in white t-shirts, with Cozma's picture on the front and his #8 on the back.