Thusnelda Mercy was born in Marseille in 1977, and grew up in Wuppertal . 
After working as a dancer and actress with the Theater der Klänge in Düsseldorf/ Germany, she pursued her study of dance at the Folkwang Universität of Arts in Essen/ Germany, where she also worked with Taiwanese artist Kuo-Chu Wu (1970-2006) in his choreographies as a dancer and as his assistant. 
At the university, she was introduced to the work of Juan Kruz de Garaio Esnaola, for whom she worked as an assistant and which brought her 2002 to Berlin, where she collaborated with the German choreographer Sasha Waltz on the creation of NoBODY and continues to work with her as a guest dancer since.

Starting in 2001, she danced in Pina Bausch’s (1940-2009) Rite of Spring and in 2003 joined the Tanztheater Wuppertal dancing their repertoire pieces as well as participating in many creations. In 2008, Pina asked her to be her assistant on the creation of Sweet Mambo. Since 2015 she regularly comes back as an guest artist.
Thusnelda also plays in the film PINA by the German filmmaker Wim Wenders.

Since 2009, in parallel to her work with the Tanztheater Wuppertal Pina Bausch, she, Clémentine Deluy, and Damiano Ottavio Biggi have been developing the Trio CDT.  Which is both a choreographic project that has produced his own and other pieces, such as 2009 Herbst choreographed by Malou Airaudo and SAMUEL-titre de travail-  directed by Pascal Merighi in 2015, and a pedagogical work that has taken the form of intensive workshops in Germany, India, Italy, Argentina, and Chile. 
In 2013, the French choreographer Lucas Manganelli put her on stage in the solo piece Agrégat during the Dañsfabrik Festival in Brest/ France.
2014 in collaboration with Mare e.V. and Ada, she takes over the organization of the Bachibouzouk- Festival and participates as a performer in the Bachibouzouk - Special under the direction of Pascal Merighi. 
The artistic encounter with the actress and writer Florence Minder in 2015 leaded to the collaboration on the creation of the Solo Sharing a Power Socket with the Premiere for the FAA (Fabrique Autonome des Acteurs) Festival in France.
In the same year she works with fabien prioville company and creates the piece SOMA Project in collaboration with Japanese artists.
She continues her career as a choreographer with her latest piece for 22 students This is my Now at the Folkwang University of Arts in Essen.
Since 2017 she is co-director of the merighi I mercy Company where she creates pieces in collaboration with Pascal Merighi such as SAMUEL, WAK.NTR Rehab. and Songs of Childhood, a duo with the dancer and her father Dominique Mercy, a Sadler’s Wells production.
She continues her career as a choreographer with her latest creation PARTITA for the Ballet de l’Opéra national du Rhin.


Thusnelda Mercy also has been working as a director and dancer on different Dance-Video-Projects. The dance film WITH IN was made 2017 in and for the Tony Cragg exhibition at the Von der Heydt Museum in Wuppertal.
She is also giving Workhops and Masterclasses around the world.
She got selceted with her film Bataville 1931-2002 in the WomenCineMakers Biennale Edition 2018 and the Thessaloniki Cinedance International Festival.