Martina Welschenbach received her musical training in her home town at the Stuttgart University of Music, the Guildhall School of Music and the Royal College of Music in London. During her studies, she made guest appearances at the Staatstheater Stuttgart and the National Theatre in Zagreb. 

In 2005, she became a member of the International Opera Studio at Zurich Opera House and was quickly accepted into the permanent ensemble. Martina Welschenbach moved to the Deutsche Oper Berlin for the 2008/09 season. Here she sang Musetta/La Bohème, Gretel/Hänsel und Gretel, Oscar/Un ballo in maschera, Ännchen/Der Freischütz and Echo/Ariadne auf Naxos as well as Clorinda/La Cenerentola, Susanna/Le nozze di Figaro, Zerlina/Don Giovanni, Micaëla/Carmen, Pamina/Die Zauberflöte, Woglinde/Das Rheingold and Götterdämmerung, Karolka/Jenufa, Solveig/Peer Gynt, Liu/Turandot and Füchslein Schlaukopf/Schlaues Füchslein.

In the course of her career, Martina Welschenbach has worked with conductors Christoph Eschenbach, Vladimir Fedosejev, Nikolaus Harnoncourt, Cornelius Meister, Ingo Metzmacher, Carlo Rizzi, Sir Donald Runnicles, Nello Santi, Peter Schneider, Franz Welser-Möst, Jonathan Nott, Sir Simon Rattle and with renowned directors such as Claus Michael Gruber, Jens-Daniel Herzog, Martin Kuschej, Carlo Lievi, Christof Loy, Giancarlo del Monaco and David Pountney.

In the 2012/13 season, she made her highly successful debuts as Freia in Wagner's Das Rheingold and Eva in Die Meistersinger von Nürnberg, opening the door to the German repertoire.

Guest appearances and concerts have taken her to Vienna, Paris, Lucerne, Stuttgart, Düsseldorf, Eutin and Leipzig. Highlights were her celebrated debut at the Opéra National de Paris as Regina in Mathis der Maler under Christoph Eschenbach, the role of Thekla/Wallenstein with the ORF under Cornelius Meister at the Vienna Konzerthaus, Fiordiligi/Così fan tutte in a concert performance under Marcus Bosch, Tatjana/Eugen Onegin in several concert performances with the Nordwestdeutsche Philharmonie and her debut with the Berliner Philharmoniker in Claude Debussy's La Damoiselle élue under the musical direction of Sir Donald Runnicles.

Martina Welschenbach has been freelancing since the 2015/16 season. She continues to be a welcome guest at the Deutsche Oper Berlin with roles such as Irene in Wagner's Rienzi and Senta/Der fliegende Holländer. Important role debuts and guest appearances included the title role of the opera Lulu at the Wuppertaler Bühnen, Marschallin/ Der Rosenkavalier and Leonore/ Fidelio at the Bonn Theatre, Senta/Der Fliegende Holländer again at the opera houses in Nantes/Angers and Rennes and the premiere of Jan Dvořák and Philipp Stölzls' music theatre revue “Phantoms of Opera” (a staged gala of the genre's arias) at the Mannheim National Theatre. This was followed by her first Sieglinde/ Walküre under the baton of Nicholas Milton and the direction of Aron Stiehl at the Stadttheater Klagenfurt before she sang Elsa/ Lohengrin for the first time at the Teatro Comunale di Bologna under the direction of Asher Fisch in autumn 2022. At the Leipzig Opera in 2023, she was Ellen Orford in the premiere cast of Peter Grimes conducted by Christoph Gedschold and directed by Kay Link, and at the Staatstheater Braunschweig she sang Sieglinde in a concert performance of Die Walküre conducted by Srba Dinić. 

In the concert repertoire, she has appeared, among others, as the Peri in Das Paradies und die Peri by Robert Schumann with the Robert-Schumann-Philharmonie Chemnitz and the MDR-Rundfunkchor. She performed Vier letzte Lieder by Richard Strauss at the International Festival Anima Mundi in Pisa with the pianist James Baillieu, as well as Lyrische Symphonie by Alexander von Zemlinsky under the direction of Stefan Blunier with the Orquestra Sinfónica do Porto Casa da Música. She also sang in Stabat Mater by Gioachino Rossini at the IMAD Festival Paderborn.

In the coming season, she will appear in Palermo with the Orchestra Sinfonica Siciliana under Josep Caballé Domenech, performing Zemlinsky’s Lyrische Symphonie and excerpts from Die tote Stadt by Erich Wolfgang Korngold.

In the previous as well as the current season, she once again sings the role of Senta in Der fliegende Holländer at the Oper Leipzig. At the Teatro Malibran of the Gran Teatro La Fenice, she appeared in Der Protagonist by Kurt Weill in the leading female role, in a new production by Ezio Toffolutti under the musical direction of Markus Stenz. With the end of the season she returns to the Deutsche Oper Berlin for the Ring cycle revival, singing Freia in Das Rheingold and Helmwige in Die Walküre.