The 1970s were crucial for the Theatre on a String. In 1972, the ensemble was professionalized and for instance J. Pecha, B. Polívka, M. Donutil, J. Bartoška, K. Heřmánek or P. Zedníček joined the theatrical engagement with Petr Oslzlý as a dramaturge. In 1973, Divadlo v pohybu (Theatre in Motion) festival organized by the Theatre on a String took place for the first time.

Individual directors were highly profiled, and their work was characterized by a distinctive handwriting. Eva Tálská tended to theatrical adaptations, staged poetry, nonsense texts and later to productions intended for the children's audience, her work was characterized by lyricism and metaphoricity. Zdeněk Pospíšil devoted himself to montages and also to theatrical adaptations, on which he collaborated with the then forbidden playwright Milan Uhde. He also initiated the launch of a children's studio, which he had led until 1980, when he emigrated. Peter Scherhaufer was strongly influenced by the epic theatre of Brecht, he staged a large number of dramatized prose works. He was also involved in the synthesis of drama with pantomime, opera, ballet and clownery, creating multi-genre productions that became iconic for the Theatre on a String - such as the 1974 production of Commedia dell'arte. The actor Bolek Polívka also began to direct his own authorial projects there.

The productions that were subsequently created brought the Theatre on a String into wider awareness and, above all, into the European context. In 1974, the theatre first went abroad, namely to the festival in Wroclaw, Poland, and a year later it took part in the international festival in Nancy. In 1976, the ensemble with productions of Commedia dell'arte and Am a Ea (Adam and Eve) participated in two festivals in Italy, and in 1978 in the first international meeting of independent theatres in Stockholm.

Artistic directors: Zdeněk Pospíšil (1972-1974), Peter Scherhaufer (1974-1976), Petr Oslzlý (1976-1980)