J. M. Smith, Scott helped found the avant-garde McGill Fortnightly Review (1925-1926), a little magazine now synonymous with modernism in Canadian poetry. He was also co-editor of its short-lived successor, The Canadian Mercury (1928-1929). In 1936 he helped edit the first anthology of modern Canadian poetry, New Provinces: Poems of Seven Authors. In 1942 he was one of the organizers of Preview, the dominant literary magazine of the decade. In March 1944 he received the Guarantor's Prize from Poetry: A Magazine of Verse for a group of war poems.

Scott's first collection of poems, delayed by the Depression, was Overture (1945), followed by Events and Signals (1954); a collection of satires, The Eye of the Needle (1957); Signature (1964); Selected Poems (1966); Trouvailles (1967); and The Dance Is One (1973). His poetry developed in four successive stages. In the late 1920s he wrote a northern landscape poetry influenced by the Imagists, by T. S. Eliot's fertility myth, and by Henri Bergson's elan vital. In the 1930s, in response to the Depression, he wrote a basically socialist, often satiric, program poetry: some of these poems—notably "Social Notes"—are blunt satires on social evils. In the 1940s his preoccupation with landscape and political reform was fused into a larger humanist structure. In the 1950s and 1960s, in response to an emerging Quebec nationalism, Scott became a pioneer translator of Quebecois poetry.

His poetic subject is most often man (in the generic sense) silhouetted against a natural horizon. His characteristic metaphors develop from the exploration of man's relationship to nature and society: they involve time and infinity, world and universe, love and spirit—terms that emerge as 20th-century humanist substitutes for the Christian vocabulary. A typical Scott poem moves from the natural landscape, as in "Laurentian Shield" ("Hidden in wonder and snow, or sudden with summer, / This land stares at the sun in a huge silence"), or from a specific image—the great Asian moth of "A Grain of Rice," for example—to a consideration of the significance of the image in the larger pattern of human life.

Distressed by the social misery of the Depression, Scott became active in left-wing political movements such as the Fabian-inspired League for Social Reconstruction (1932), which published Social Planning for Canada in 1935. He was national chairman of the Co-operative Commonwealth Federation (now the National Democratic Party) from 1942 to 1950 and co-author of Make This Your Canada: A Review of CCF History and Policy (1930). He wrote Canada and the United States (1941) after a year spent at Harvard on a Guggenheim fellowship. He also contributed to the important symposium Evolving Canadian Federalism (1958) and was a co-editor of Quebec States Her Case (1964), a series of essays on the new Quebec nationalism. Scott, an authority on constitutional law and civil rights, was described by the legal historian Walter Tarnopolsky as an "architect of modern Canadian thought on human rights and fundamental freedoms." He argued several major civil rights cases before the Supreme Court of Canada, including Switzman v. Elbing (1957), Roncarelli v. Duplessis (1958), and Brodiev. The Queen (1961), better known as the Lady Chatterly case.

In 1952 Scott was briefly a technical-aid representative for the United Nations in Burma; from 1961 to 1964 he was dean of law at McGill; and from 1963 to 1971 he was a member of the Royal Commission on Bilingualism and Biculturalism. Scott—who contributed equally to Canadian law, literature, and politics in both official languages—was elected to the Royal Society of Canada in 1947, awarded the Lorne Pierce Medal for distinguished service to Canadian literature in 1962, and received a Molson Prize for outstanding achievements in the arts, the humanities, and the social sciences in 1967. His career as an interpreter of Quebec poetry culminated with a Canada Council Translation Prize for Poems of French Canada (1977); his work as a social philosopher culminated with a Governor General's award for Essays on the Constitution: Aspects of Canadian Law and Politics (1977); and his poetry was crowned with a Governor General's award for The Collected Poems of F. R. Scott (1981).