Shaped by a Baptist upbringing in the rural South and endowed with a quick mind, down-home manner and penchant for pragmatism, he took official Washington by surprise.

It wasn't Jimmy Carter this time but rather the man be chose to head the Labor Department - a 48-year-old University of Texas economist and labor manpower specialist named Freddie Ray (he's dropped the Freddie) Marshall, one of those "outsiders" whom Carter talked so much about bringing to Washington.

As it turned out, Marshall was not that much of an outsider. For a decade or more he was one of those semi-visible academicians who, from the periphery of government - subsidized scholarship and demonstration projects, help shape national policy - in his case mainly in the area of job development and training for rural residents and monorities.

Before his appointment, he was in Washington at least two days a week because membership on a half dozen advisory panels sponsored by the Labor Department and other governmental agencies and the presidency of the National Rural Center, a nonprofit research organization with a $750,000 annual budget that he founded last year focus national attention on rural problems. He - or research groups headed by him - received $1.5 million in grants from the Labor Department alone.

On projects ranging from improving the lot of workers in Texas citrus groves to getting more blacks into union apprenticeship programs in northern cities, he also established a close rapport with labor and some segments of industry.

Moreover, Marshall quickly gained the ultimate access to the inside: the ear of Jimmy Carter.

Asked to name some of the people the President listens to most on economic policy, Charles L. Schultze, chairman of the Council of Economic Advisers, said recently: "The only thing I can tell you on that is . . . he's very impressed with Ray Marshall. I'm not suggesting there's any dominant character, but it's clear he's very high on Ray Marshall."

So is organized labor, although it had favored former Labor Secretary John T. Dunlop over Marshall for the job he now holds and has sharply criticized the Carter's administration's economic stimulus package. Marshall was offered the job of AFL-CIO research director last year, and federation president George Meany once described him as one of the "few American professors who understands the working people."

Congress, too, seemed pleased, aside from a conservative minority that vigorously protested his nomination, charging that he was too close in his thinking to the AFL-CIO.

Even his congressional critics, gave him high marks, of a sort. "Thank goodness he is not a union organizer down there" in Texas, said Sen. John G. Tower (R-Tex.), who joined 19 other conservatives in voting against his confirmation last month, "or the story might be different, because he is a very talented young man."

Despite an easygoing charm, Marshall is neither an amiable rustic nor Texas-stereotype swashbuckler. He is very much in the mold of Carter: cool, self-confident, impatient with ideological musings that don't produce results and "very consciouse of where he came from," as an old friend noted recently.

The son of a Louisiana tenant farmer, Marshall spent most of his formative years in a Mississippi Baptist orphanage, an experience that friends say helped him develop self-reliance, respect for what he call "real work as opposed to make-work empathy for the underdog and racial tolerance."

Said Marshall in a recent interview: "What was important was that I knew the difference between make-work and the satisfaction that people can get from really knowing what you're doing is necessary."

As for religion and race, he said of his years at the orphanage, "You had an opportunity to contract what was being preached with what was happening . . . There was a good bit in the religious experience that I had trouble with . . . like what form of baptism you had to go through . . . But there were other parts of it that I thought really did make a lot of sense, especially the concept of the brotherhood of man."

After running away from the orphanage at age 15, he lied about his age and joined the Navy, returning after World War II to attend several Southern universities on the GI Bill of Rights. He received his doctorate in economics from the University of California and Rockfeller Foundation grant designed to help educate poor Southerners.

Friends say the educational aid Marshall received made him a strong believer in the benefits of governmental assistance and kept him in the South as a teacher - at least until he was enticed by the lure of trying to put his ideas into practice in Washington.

His relationship with Carter is apparently solid.

"Whatever it is, there seems to be a good chemistry there," said Charles Knapp, a University of Texas colleague who is Marshall's special assistant. "I think it's logical approach that appeals to Carter."

The relationship apparently withstood its first test, a burst of candor by Marshall about his disappointment with Carter's $31.2 billion economic stimulus package that wound up on the front page of many newspapers. Marshall would have preferred more spending for jobs and less of a tax cut, he told the Senate Labor Committee.

The next day he "clarified" the situation, telling reporters that Carter gave him all the jobs money he asked for and saying he had simply meant to express regret that governmental machinery wasn't able to absorb more jobs spending effectively . But he continued to insist that jobs spending is more effective in stimulating the economy than tax relief - a position applauded by his labor constituency.

Already Marshall's impact on policy can be seen in several ways, including some increase in projected jobs spending and the so-called "outreach" concept that he included in the administraion's special program for imployment of Vietnam war era veterans.

Under this idea, which Marshall championed during the 1960s to get more blacks into union apprenticeship programs in the building trades, prospective workers were acrively recruited for specific jobs. They were sought out in car washes, warehouses and wherever else young people go when they can't get higher-skilled, better paid work elsewhere. They were told about more promising opportunities and coached on how to cope with entry examinations and intimidating examiners.

Working under a Labor Department grant, Marshall and another University of Texas economics professor, Vernon Briggs Jr., ran across the outreach approach at a small training center in New York City, wrote about it and won support for the approach from organized labor and the Labor Department. Since the early 1960s, about 40,000 people have gone through outreach programs in more than 100 cities, according to Briggs. Marshall reportedly intends to name Ernest Greeen, head of New York program, called Recruitment and Training, as assistant secretary in charge of employment and training.

"The idea was to make things work without getting everyone defensive" about suggestings for quotas or court action, said Briggs.

But the approach was attacked as timid and overly deferential to historic exclusionary practices of many construction unions by advocates of a tougher approach, including Herbert Hill, national labor director of the NAACP.

It took the heat off unions to accept mandatory hiring goals and timetables, they argued. Marshall's whole approach, says Hill, who worked with him on a civil rights research project in the early 1960s, is "an apology for the discriminatory practices of organized labor with pretension of scholarship."

Despite at least $27.2 million spent on outreach programs by 1972, blacks have not significantly increased their proportion of jobs in skilled trades, Hill maintained in a critical study of the effort in 1974. "If it was bad then, it's worse now," he said recently.

Said William B. Gould, a Standford University law professor: "Marshall's on the side of the angels but I'm afraid he doesn't seem adequately enough worried about the institutional problem [of union discrimination] - the [kind of] gut issue that will get him in trouble with the people who support him."

Marshall spoke strongly in favor of affirmative-action programs for women as well as blacks at his confirmation hearing but made it clear in an interview recently that he will continue to pursue cooperation over confrontation whenever possible.

"Some people ought to be doing those things maybe, just investigating, attacking, pointing up the problems that society faces," he said. "But my basic inclination was always to try to work out the solutions. Now, those other people helped us a lot because they usually presented to the parties a worse alternative than we had in mind for them."

On many issues, Marshall comes down on the side of organized labor. He gives top priority to reducing unemployment, supports an as-yet unspecified increase in the $2.30 per hour minimum wage, favors repeal of Section 14(b) of the Taft-Hartley Act that permits states to enact right-to-work laws banning union shops, opposes an outright ban on strikes by public employees although he favors arbitration as the final recourse, and endorses so-called "common site" legislation to permit unionized employees of a subcontractor to picket and thus possibly shut down an entire construction project. But his enthusiasm for some of the litmus-test issues such as common-site picketing and 14(b) repeal is not great.

He opposes wage-price guidelines, favoring a cooperative effort through labor-management committees at the industry level. He favors a continuation of revenue-sharing with state and local governments but wants federal guidelines to target spending in line with national goals, such as more jobs for Vietnam veterans and an emphasis on apprenticeship programs.

He foresees, he said recently, a generally harmonious year in labor-management relations. He said he sees little likelihood of seriously inflationary wage settlements or strikes that could increase unemployment - although he said the department is closely watching several industries, including coal, where negotiations are complicated by a dissension-wracked United Mine Workers.

A compulsive worker since his days at the orphanage, Marshall has trouble obeying Carter's admonition to work normal hours and take time off with the family, which, in Marshall's case, is a closely-knit unit - wife Patricia and five children - whom he asked to vote on whether he should accept the Labor Department job. So far, friends say, he's not complaining about the verdict.