Dmitri Fedorovich Ustinov, the Soviet minister of defense who died last night at age 76, played a key role in the growth of Soviet military power, from his days as Joseph Stalin's young commissar for armaments to his more recent emergence as one of the Kremlin's four most powerful men.

Ustinov, trained as an engineer, helped direct several of the Soviet Union's most dramatic achievements, including the swift, wholesale relocation of key industries as Nazi forces advanced into Soviet territory during World War II and later, as minister of defense industry, the successes of the Soviet space program.

It was also under his guidance that the Soviet Union built up its military arsenal, developing new strategic weapons systems that put it in the same superpower status as the United States.

His efforts in these fields earned him dozens of medals and awards, including 12 Orders of Lenin, far more than any other member of the Politburo, making him probably the most honored man in the Soviet Union. In his official portraits, his chest was literally covered with medals and ribbons.

Soviet citizens knew him as one of the fixtures in their leadership, the man who for the past eight years stood ramrod straight in a moving convertible to take the salute at the Nov. 7 military parade in Red Square. His absence this year was the first clue that his health was failing.

Together with President Konstantin Chernenko, Foreign Minister Andrei Gromyko and Premier Nikolai Tikhonov, Ustinov was a member of the old guard in the Communist Party's ruling Politburo. When the Supreme Soviet, or parliament, met last month, again with Ustinov absent, a member of a younger generation -- Mikhail Gorbachev, 53 -- moved into the leadership's front row for the first time.

Of the older generation, Ustinov shared with Gromyko the longest history of continuous high-level service, surviving the vicissitudes of Soviet political life, first under Stalin, then under Nikita Khrushchev, and achieving seniority under Leonid Brezhnev.

But while his career was always linked with the military, Ustinov was a civilian. Until 1976, when he became defense minister, he had the rank of a three-star colonel general in the engineer corps. His official biography shows him as having served as a volunteer in the Red Army from 1922 to 1923.

His lack of military credentials was apparently one reason some members of the Soviet military establishment opposed his candidacy for defense minister in 1967. The post that year went to Marshal Andrei Grechko, which was considered a victory for the professional military in their efforts to gain greater say in setting policy.

Nine years later, Ustinov was given the job, which at the time surprised some western analysts. He was then 68, already beyond retirement age. But unlike Grechko in 1967, whose appointment was delayed by infighting until 12 days after his predecessor's death, Ustinov's appointment was announced hours after Grechko's funeral. This indicated a quick, firm and nondebatable decision by Brezhnev to put the job under civilian control.

At the same time, in April 1976, Ustinov was made a full general and within three months he was elevated to the most exalted rank in the Soviet military -- marshal of the Soviet Union. He was only the fifth political appointee in Soviet history to become a full marshal.

But if the defense minister's job had to go to someone outside the military, Ustinov was an obvious choice. His work in and support for the military-industrial complex made him more than an ordinary civilian in the eyes of the military establishment.

Moreover, Ustinov by then was in the Politburo, having moved up to full membership a few months before Grechko's death after more than a decade as an alternate member. This avoided the awkwardness of having to induct a new defense minister into the Kremlin's ruling elite.

During Brezhnev's declining years, Ustinov's role expanded, particularly after the death of veteran ideologist Mikhail Suslov in January 1982. By the time Brezhnev died in November 1983, Ustinov was in a position to act as kingmaker, lending his support first to Yuri Andropov and then, after Andropov's death, to Chernenko.

In his speeches and statements, Ustinov took a tough line on the need to match any attempt by Washington to achieve military superiority. In May this year, he warned the Reagan administration against thinking that "it is possible to threaten or pressure the Soviet Union into unilateral concessions."

A member of the Communist Party since 1927, Ustinov had risen steadily in the party hierarchy, joining the Central Committee in 1952 and the Secretariat in 1965. But his real power came as head of the defense establishment, controlling a vast sector of the Soviet economy that has impact on virtually every region of the country.

Known as a tough, shrewd executive, Ustinov also had the engineering background that qualified him to judge, as well as expedite, the production of Soviet armaments.

Ustinov was born Oct. 30, 1908, to working-class parents in Samara, now Kuybyshev, in the Urals, the city where the Soviet government moved after the German attack in 1941.

His first jobs were as a fitter in a paper plant, then as a diesel engineer. After graduating from the Leningrad Military Technical Institute in 1934, he went on to become a design engineer in a Leningrad armaments factory and, by 1938, its director.

He was only 32 in 1941 when he was tapped by Stalin to direct the Soviet Union's crash rearmament program after the shock of the German invasion. During the defense of Moscow, Ustinov took charge of local efforts to arm the city, supplying citizens with gasoline bombs in the event the Germans entered the capital.

His success in mobilizing the war effort and in evacuating vital industries east to the Urals earned him the award of Hero of Socialist Labor in 1942.

After the war, he became minister of defense industry and later, as deputy premier, supervised the Soviet space program, earning him another award of Hero of Socialist Labor.

In 1963, Ustinov was promoted to first deputy premier and made chairman of the Supreme Council of the National Economy of the U.S.S.R., charged with overseeing the decentralization of Soviet bureaucracy ordered by Khrushchev.

That program was scrapped when Khrushchev was ousted in 1964, and by 1965, Ustinov was in the party's Secretariat with overall responsibility for the defense industry.

During his tenure as defense minister, the Soviet Union continued its program of weapons modernization, increasing the number of warheads on its missile launchers, expanding its Navy and developing and deploying long-range ground- and sea-based cruise missiles in response to similar weapons deployed by the United States.

According to the London-based International Institute for Strategic Studies, the Soviet armed forces also underwent organizational changes under Ustinov, with the grouping of forces into three geographical "theaters."

The obituary released tonight by the official Soviet news agency Tass lauded Ustinov's role in "raising the combat preparedness" of the Soviet armed forces. "Marshal of the Soviet Union Dmitri Ustinov firmly and unswervingly implemented the party's policy of ensuring the defense capability of the Soviet state," the obituary said.