As a player he spent the majority of his career playing for Legia Warsaw as a defender, and represented Poland 29 times internationally.

[3] Following a major injury in a friendly match, Gmoch began his coaching career, starting as assistant manager for Legia Warsaw between 1969–71.

While, in 1970-71 Legia finished runner’s up of Poland, and reached the quarter-finals of the European Champions Clubs’ Cup losing to Atlético Madrid.

During the World Cup, he reached the second round where ultimately Poland finished 5th in the final rankings,[4] only losing to Brazil, and eventual winners and hosts Argentina.

He later joined Apollon Athens in 1981-82, and Larisa in 1982-83,[7] where he finished runner up in the Greek league, the first time a provincial team managed this feat.

He notably commentated Champions League matches for the Greek Television ERT, as well as International Tournaments in Poland for channels Polsat and TVP.

On 15 November 2010, Gmoch took over as the caretaker manager of Panathinaikos, following Nikos Nioplias, who resigned after a string of mediocre results in the first part of the 2010–11 season.