Laura Gray was born Laura Slobe, in Pittsburgh in 1909, to a prosperous Jewish family, but she grew up in Chicago. At age 16, she enrolled at the Art Institute of Chicago. By 19, she began exhibiting paintings, winning a number of prizes, and her paintings continued to appear in exhibits at the Institute and in several galleries. By the late 1930s, she began to produce and exhibit avant-garde sculpture as well, and eventually became known more for her sculpture than her painting. Her work continued to be shown in exhibits in the Chicago area until 1944.

From spring 1939 through September 1940, Gray worked for the Illinois division of the federal Works Progress Administration's Painting and Sculptures Section, creating works of art for the program , as well as serving as an art instructor for it in Illinois and in several other states, traveling as far afield as Oregon. Gray became friendly with a group of other Chicago avante-garde artists attracted by Troskyism. One of the group was George Perle (born George Perlstein, 1915-2009), a composer, whom she married in 1940. (In the 1960s Perle became a major theorist of serialism--a method of composition associated with Schoenberg's 12-tone technique—and was awarded a Pulitizer Prize and a MacArthur fellowship in 1986.)

In 1942 Gray and Perle joined the Trotskyist organization, the Socialist Workers Party (SWP), in Chicago. Not long after joining the SWP Laura Slobe took the name "Laura Gray," a "party name" (a pseudonym adopted by a member of a political party to hide his or her real identity to avoid political, legal or workplace persecution, surveillance and discrimination). Within a few weeks, she was assigned by the SWP to assist with organizing workers in the automobile industry, and she employed her artistic skills by drawing cartoons for a union shop paper. The SWP's branch organizer recognized her skill and encouraged her to submit a cartoon to the SWP's newspaper, The Militant. Gray's first cartoon inThe Militant appeared on March 4, 1944, and thereafter at least one of her cartoons appeared (under the name "Laura Gray") inThe Militant almost weekly for the rest of her life, and she became the paper's staff artist. Many of Gray's cartoons published inThe Militant were also reproduced in Trotskyist and Trotskyist-associated labor publications in as many as 20 countries. While many praised her work as a graphic artist—one scholar describing her cartoons as "naturalistic and powerful, in the tradition ofThe Masses' Boardman Robinson, and warrant[ing] comparison to artists such as Hugo Gellert and Robert Minor," Gray herself did not consider her cartoons to be serious art; she remained devoted to sculpture and painting.

Gray and Perle moved to New York City soon after World War II. They were legally divorced in 1952, but remained close friends. In the late 1940s and early 1950s she lived on and off with Duncan Ferguson (1901-74), a sculptor and fellow SWP member. Evidently her work forThe Militant was not enough to support Gray; she also worked simultaneously at a number of temporary jobs, including painting mannequins and creating window display art for department stores. As the years went by she devoted less and less of her time to her own art as a sculptor and painter, although she longed to return to it. Gray's health was fragile; she had suffered from tuberculosis in her early twenties, and had had a lung removed in 1947. She died in 1958, at the age of 49, when she contracted pneumonia that rapidly turned fatal. A prize in sculpture was established in her name at the Art Institute of Chicago, and a George Perle composed a quintet for strings titled "In Memory of Laura Slobe."

Gray used a large format for her cartoons. She was particularly effective in capturing political personalities (including U.S. Presidents Roosevelt, Truman, and Eisenhower) and sharply analyzing both national and international issues, particularly those that affected workers. Her subjects (chosen by The Militant's editorial committee) include racism (especially the Emmett Till case, Jim Crow legislation, the poll tax, and the Ku Klux Klan), labor and unemployment, and mainstream U.S. political parties. During World War II, subjects of satire included the War Labor Board, the no-strike pledge, and the Little Steel Formula; postwar the Marshall Plan, the Korean War, the red scare of the 1950s, and the United States government's embrace of dictators such as Spain's Francisco Franco, were included among her targets.