Born in Limanowa, she began her musical education as a violinist. Vocal studies at the K. Lipiński Academy of Music in Wrocław in the class of prof. Tadeusz Pszonka, which she graduated with honors. After graduation, she improved her qualifications by pursuing postgraduate studies in the field of oratorio music, and in 2015 she defended her doctorate in arts.She developed her vocal skills by taking part in championship injuries in the country and abroad.
As a third-year student, she made her debut on the stage of the Wrocław Opera in the role of the Third Lady in the opera "The Magic Flute" by W.A. Mozart under the direction of T. Zathey and since 2011 she has been a soloist of this Opera. On boards this Opera, she created many opera roles, for which she gained recognition from critics and viewers. In 2017, she received the title of " Opera Singer of the Year" for the role of Azucena in the opera "Il Trovatore" and the readers of Gazeta Krakowska chose her "Personality of the Year 2016" in the field of culture.
She was a finalist of the 7th International Moniuszko Competition in Warsaw in 2010. She received the Third Prize at the 14th International Vocal Art Competition named after Ada Sari in Nowy Sącz in 2011, Second Prize at the 1st International Jan Kiepura in Krynica Zdrój in 2013, First Prize at the 2nd International Competition. Andrzej Hiolski in Kudowa Zdrój in 2013, the Second Prize at the 7th International Vocal Competition in Zdar nad Sazavou, Czech Republic in 2014, and the Third Prize and Special Prizes at the 11th International Gabriela Beňačková Competition in Jihlava, Czech Republic in 2018.
She was a scholarship holder of, among others, the Ministry of Culture and National Heritage and the Richard Wagner Stipendienstiftung in Bayreut.
In 2008-2018, she gained the recognition of Polish opera theaters and philharmonics in Gdańsk, Kraków, Białystok, Katowice, Kalisz and Warsaw. In the 2019/2020 season, as Santuzza, she took part in performances of Pietro Mascagni's Peasant Chivalry at the Stadttheater Bremerhaven. Since December 2020, she has been a soloist of the Theater in Magdeburg. In February 2022, she sang the role of Emerentz Zernitz in the world premiere of the opera Grete Minde by the German composer Eugen Engel. In June 2023, she made her debut on the stage of the Grand Theater of the National Opera in the role of Mrs Sedley in the opera "Peter Grimes" by B. Britten, directed by Mariusz Treliński.
She is recognized by Polish and German music critics who appreciate her passionate and powerful voice and stage personality, calling her the engine of stage energy.
Jadwiga Postrożna's operatic repertoire includes the following roles: Miss Sadley (Peter Grimes, B. Britten), Miss Quickly (Falstaff, G.Verdi), Azucena (I.Trovatore, G.Verdi), Dalila (Samson et Dalila, C. Saint-Seans , Santuzza, (Cavalleria Rusticana, P. Mascagni), Fenena (Nabucco, G.Verdi) Suzuki (Madama Butterfly, G. Puccini), Ulrica (Un ballo di maschera, G.Verdi), Kończakówna (Prinz Igor, A. Borodin ), Olga (Eugene Onegin, P.I. Tchaikovsky), Marceline (The Marriage of Figaro, W.A. Mozart), Flora Bervoix (La Traviata, G. Verdi), The Third Lady (Die Zauberflöte, W.A. Mozart), Berta (The Barber of Seville, G. Rossini) , Old Lady (Candide, L. Bernstein), Tisbe (La Cenerentola, G. Rossini), Cuniza (Oberto, G. Verdi) Cześnikowa (Straszny Dwór, St. Moniuszko).
Her performances have taken her to concert halls in Poland, the Czech Republic, Bulgaria, Russia, China, Germany, Austria, Slovakia, Hungary and Switzerland. She has collaborated with directors such as: M. Znaniecki, M Treliński, J. Aleksandrov, L. Adamik, K. Lada, A. Leitenshneider and conductors, among others: M Klauza, A Skryleva, Ch. Olivieri-Munroe, T. Kozłowski, J. Kasprzyk, M. Nałęcz-Niesiołowski.