Croy spent his entire footballing career at BSG Sachsenring Zwickau (today FSV Zwickau), with which he won the East German Cup in 1967 and 1975. He was one of East Germany's few international players not to play for a top club such as Dynamo Dresden, FC Carl Zeiss Jena, or FC Magdeburg. As such, Croy did not get the chance to play frequently in European competitions and did not gain the international fame he deserved. Though tall (186 cm), he was an outstanding shot-stopper capable of amazing reflexes on his line. Combined with an excellent command of his penalty area, first-rate ball-handling skills, and above-average consistency, this quality made Croy one of the best goalkeepers of his time and arguably one of the best ever. East and West German media alike often placed him on an equal footing with his contemporaries Sepp Maier and Dino Zoff, two of the game's all-time legends.
Croy earned his first East Germanycap in May 1967 against Sweden (1–0). He was the starting goalkeeper during East Germany's only World Cup appearance in 1974. In particular, Croy stood in goal for the GDR's historic 1–0 victory over its West German neighbor in the only match ever to oppose the two Germany national teams. Two years later, Croy celebrated his greatest sporting triumph with the win of the gold medal in the Olympic football tournament. Croy went on to play 86 times for his country, the last one a 5–0 victory over Cuba in May 1981.
Croy was elected GDR Footballer of the Year in 1972, 1976, and 1978 by the East German football press. He played 372 East Germany first-division matches in his career.
At the end of his footballing career, Croy worked as a football instructor for some time. From 1991 to 2001, he served as city commissioner for education, culture, and sports in his hometown of Zwickau. Today, Jürgen Croy is the managing director of the Zwickau Chamber of Commerce, Tourism, and Culture.