His work was influenced by his Jewish heritage and Eastern religions as well as by artists including Altdorfer, Grünewald, Caravaggio, Rembrandt, Blake, Bresdin, Ensor and Soutine.

In the eighth grade he received a scholarship to a program for gifted high school students at the Museum of Fine Arts.

He hung William Blake prints on the walls of the settlement house, and encouraged students to synthesize images from multiple sources.

Ross, whose leanings were more academic,[note 3] taught Bloom how to handle paint in the style of the earlier masters.

Thus Zimmerman and Ross fostered respect for artistic tradition while also teaching that art was not merely a matter of copying, but of using one's imagination to create a formal design: ideas that would later influence a school of painting known as Boston Expressionism.

[10] He first received national attention in 1942 when thirteen of his paintings were included in the Museum of Modern Art (MoMA) exhibition Americans 1942: 18 Artists from 9 States, curated by Dorothy Miller.

Two were titled The Synagogue, another, Jew with the Torah; Bloom was actually criticized by one reviewer for including "stereotypical" Jewish images.

"[14] In 1950 he was chosen, along with the likes of de Kooning, Pollock, and Arshile Gorky, to represent the United States at the Venice Biennale.

[15] That same year Elaine de Kooning wrote about Bloom in ARTnews, noting that in paintings such as The Harpies, his work approached total abstraction: "the whole impact is carried in the boiling action of the pigment".

[16] In 1951 Thomas B. Hess reproduced Bloom's Archaeological Treasure in his first book, Abstract Painting: Background and American Phase, along with works by Picasso, Pollock, and others.

[17] As abstract expressionism dominated the American art world, Bloom became disenchanted with it, calling it "emotional catharsis, with no intellectual basis.

The series began in 1943 when artist David Aronson invited Bloom to accompany him on a trip to a morgue, where he was working on sketches for a painting, Resurrection.

Bloom was both repelled by and drawn to the sight of the decomposing bodies, and painted them, he explained later, in hopes of coming to terms with death.

The upright posture is reminiscent of Grünewald's crucified Christ in the Isenheim Altarpiece, Bloom's favorite painting.

Bloom believed that death was a metamorphosis from one form of life to another as the body was consumed by living organisms: a process for which resurrection can be seen as a metaphor.

Joseph Gibbs wrote, "After a moment of repugnance, one becomes aware that within the artist's seeming absorption in death and decay is contained the resurrection—the relative unimportance of fugitive flesh as opposed to the indestructibility of the spirit.

[21] Some critics have suggested that these images arose from Bloom's exposure to pogroms in his home country, and later, reports of the Holocaust.

He taught himself how to play the sitar, oud, and other instruments, and in 1960 helped James Rubin found the Pan Orient Arts Foundation, a group that organized concerts and collected recordings by Indian artists.

Asked why he chose to depict only the first level, filled with frightening creatures, Bloom replied, "You draw your experience.

His oil paintings of the Lubec, Maine, woods in the late 1970s exude what critic Holland Cotter called a "disturbed, ecstatic energy".

Bloom was a close friend of the composer Alan Hovhaness and the Greek mystic painter Hermon di Giovanno.

Bloom encouraged di Giovanno in his art, providing him with a set of pastels with which he executed his earliest paintings.