Loretta Pflaum was born in Vienna in 1972. She studied directing at the Max Reinhardt Seminar in Vienna and acting in New York and Rome. From the mid-1990s on, she regularly made appearances in TV productions, e.g. playing guest roles in crime series such as "Kommissar Rex" and recurringly in "Tatort". In Hermine Huntgeburth's "Der Hahn ist tot" (2000), she appeared in one of the main roles as the love interest of an elderly man. She was a member of the ensemble in the comedy "Bis dass dein Tod uns scheidet" (2002, TV) playing alongside Senta Berger and Günther Maria Halmer as well as in the drama "Für immer verloren" (2003, Director: Uwe Janson) with Veronica Ferres and Walter Sittler. Loretta Pflaum also played important roles on the big screen for example in Roland Düringer's tragic comedy "Die Viertelliterklasse" (AT 2005) and as the girlfriend of an innocent terrorist suspect in Benjamin Heisenberg's "Schläfer" ("Sleeper", AT/DE 2005). Michael Glawogger cast her for his social study "Slumming" (AT/CH 2006) as a hippie girl, for director Niki Stein, she played the partner of the GDR "escape helper" Michael Gartenschläger (called Manfred Brettschneider in the film).

In the following years, Pflaum mainly appeared in guest roles in TV series, such as "SOKO Kitzbühel" (2009), "Schnell ermittelt" (2010) and "SOKO Leipzig" (2012). For Lawrence Tooleys social drama "Headshots" (AT/DE 2010), she worked as producer, co-author, costume designer and lead actor. The film was shown at film festivals in Vienna, Rotterdam and Oldenburg among others. After a smaller role in Hendrik Handloegten's genre-mix "Sechzehneichen" (2012), Loretta Pflaum took a break from acting for a couple of years. In 2017, she made her comeback starring as the protagonist's wife in the social drama "Jetzt. Nicht.". Also in 2017, she again worked with director Lawrence Tooley, this time as producer and actor for the social love drama "Gatekeeper" (AT).