Graduated from the Odessa I. I. Mechnikov National University with a degree in Classical Philology. Throughout different episodes of her career she was leading numerous institutions: Moscow Center of Arts at Neglinnaya, Tatintsian Gallery and Museum and Exhibition association of "Manege", D. A. Nalbandyan's museum-studio space and museum of V. A. Sidur. Co-founder of the Proun Gallery and a member of the experts council (2010) and the jury (2014) for the Kandinsky Prize awards. Marina Loshak was appointed director of the Pushkin State Museum of Fine Arts on July 1, 2013.
Maintaining the tradition established by the founder of the Museum Ivan Tsvetaev, she develops a large project Pushkin Museum XXI aiming to show the interaction between the classical and contemporary art through temporary exhibitions, including October by Cai Guo-Qiang (2017) Fabrizio Plessi. The Soul of Stone (2018), There is a Beginning in the End (2019, Venice) and many others.
In 2017 the Pushkin Museum participated in the Venice Biennale for the first time with the exhibition Man as Bird. Images of Travel. Marina Loshak pursues development of strong international connections, enabling to hold large exhibitions such as Renaissance Venice. Titien, Tintoretto, Veronese (2017), The Age of Rembrandt and Vermeer. Masterpieces from the Leiden Collection (2018), Picasso & Khokhlova (2018–2019), Collection of Fondation Louis Vuitton. Selected works (2019), etc.
She pays a special attention to exploring collecting activity. The exhibition Chtchoukine. Biography of a Collection (2019), unparalleled both in terms of scale and content, told the history of Serguey Chtchoukine's collection through his personality, the story of his family and a larger historical context. The reunification of the collection that remains divided between Moscow and St. Petersburg since 1948 was a major event for the Russian culture. An exhibition dedicated to another collector, Ivan Morozov, is planned.
Marina Loshak supervises a large scaled renovation of the Pushkin Museum that will result in a "Museum Town" with 12 buildings accessible for visitors. The project was launched in 2009 and is expected to be completed by 2027 when the Pushkin Museum will turn into a museum district with its own depositary, research centre, temporary exhibitions and permanent display galleries as well as spaces for lecture activities and open-air exhibitions.