For 22 years Harry J. McGuirk carefully built and nurtured the image of a consummate politician, a man who never led with his best punch but always had it lurking. Now, as he prepares to take the biggest risk of his career, he finds himself fighting against the very image he made for himself.

Politicians talk among themselves about state Sen. McGuirk's hidden agendas and speculate about what he is really up to. But once the July 6 filing date passes and McGuirk begins spending money, that talk will fade. Then it will be up to McGuirk, a man who has never won a race outside his Baltimore district, to convince voters statewide that he is a viable candidate for governor.

Therein lies the image problem.

If Webster's ever decided to include a definition of the term "Baltimore Pol" in its tome, it might include a picture of McGuirk. Start with the appearance: short and stocky with slicked-back, whiter-than-white hair, three-piece suits, the pants often cuffed. And the pinky rings, large and flashy, impossible not to notice.

Then there is McGuirk's political spawning ground: The Stonewall Democratic Club in south Baltimore is one of the bastions of traditional city politics, going back to the days when patronage, arm-twisting and walk-around money were as much a part of the political process as voting booths.

McGuirk and Marvin Mandel came from opposite sides of town but they came to be known as the ultimate players of the political game. And, they were close friends. McGuirk testified on Mandel's behalf at the former governor's trial and when Mandel returned from prison last December McGuirk was the only major elected official to greet him at the airport.

Finally, there is McGuirk's reputation as a friend of special interests. During his eight years as chairman of the Senate Economic Affairs Committee, he has worked closely with the banking and insurance industries.

There is no evidence that McGuirk has ever been involved in nefarious activities. In fact, he is widely regarded by colleagues as the most effective and influential legislator in Annapolis.

"He's an anomaly," said Prince George's Del. Gerard F. Devlin. "He comes off as shallow and introverted, as a back-slapping old pol. But there's an awful lot of substance there. He's very bright, he's a master of massaging people and he knows as much or more about the legislative process than anyone. But in an era of image politics you wonder how important substance is."

That may be the crucial question of McGuirk's campaign. In Gov. Harry Hughes, McGuirk is facing a prototype media candidate and a man who won in 1978 by running against the old-line traditions that, in addition to producing Mandel and his scandal-scarred administration, produced McGuirk. Those who know, say it takes a minimum of $1 million in a statewide campaign to mount an effective media campaign down to the grassroots that can beat an incumbent. McGuirk is hoping to beat Hughes with half that amount.

"You have to wonder," said one McGuirk colleague, "how Harry McGuirk will play in Montgomery County."

McGuirk smiles at these questions just as he smiled in March when people refused to believe he was really running for governor. "This race is Harry Hughes' race to win or to lose," he said. "To tell you different would be foolish. But I believe he's going to make mistakes between now and Sept. 14. He has to. He's a human being.

"I'm in this race for one reason: I honestly believe I can win. People say I have a name identification problem, but a lot of people in this state don't know Harry Hughes. I don't think this state can afford to wait three years for decisions to be made like it did before this past session."

His clear blue eyes softened for a moment. "There's one other reason: I'd like to be governor." Born Into Politics

Harry James McGuirk was born Nov. 7, 1923, the youngest of 10 children in a Baltimore working class family. Because the family home was overflowing, McGuirk moved in with his uncle, Guy Bryant, when he was 4. He was raised by Bryant, an influential city politician and one of the cornerstones of the Stonewall club during the 1930s. McGuirk was weaned on politics, growing up with Stonewall as his recreation center.

At an early age he made a promise to his aunt not to drink until he was 21. She died before McGuirk graduated from high school and, as a tribute, McGuirk has never taken a drink. "I've sipped wine, but that's it." He kept his word through college (Maryland, Cornell and Morgan State) and through four years in the Navy.

When he returned from the Navy, McGuirk took his degree in business administration and opened a real estate business in Baltimore County. He remained an active member of Stonewall and on Jan. 12, 1960, he was appointed to the House of Delegates by Gov. J. Millard Tawes, taking the seat of William L. Hodges, who resigned when elected to the Baltimore City Council.

Somewhere during that period he picked up his famous nickname, Soft-Shoes. The derivation is disputed. Some say it started because of McGuirk's excellence as a ballroom dancer. Others attribute it to former Sen. Joseph Bertorelli, who once, being complimented on his slickness, said, "but Harry gets around more than I do. He does it so quietly I think he wears soft shoes." Others claim it comes from his ability to quietly slip in and out of the committee room to conduct other business during public hearings.

Once appointed, McGuirk quickly began shaping his image as a man who always knew more than he let on and as one of the few people in the legislature who truly seemed to understand all the bills.

"He doesn't understand everything about every bill," said Del. Paul E. Weisengoff, McGuirk's friend and south Baltimore political protege. "But he can read one portion of a bill or at least understand one part of the bill and give the impression that he understands the whole thing better than the guy that wrote it. That's part of his mystique."

During his one full term in the House, McGuirk was close to then-Speaker Mandel, and often was floor leader for bills Mandel wanted. One of the most often repeated McGuirk stories occurred during a crucial floor vote when he walked up to the rostrum and began whispering in Mandel's ear. Mandel nodded yes. McGuirk whispered some more. Again, Mandel nodded. McGuirk returned to his seat and voted for the bill. A dozen votes followed him.

What, everyone wanted to know, had McGuirk said to Mandel that had caused him to nod so affirmatively, apparently in favor of the bill? "First I asked him if he wanted some coffee," McGuirk said. "He said yes. Then I asked him if he wanted cream and sugar. He said yes again."

In 1966 McGuirk was elected to the Senate and immediately joined an insurrection designed to remove Sen. Frederick C. Malkus from the chairmanship of the Judicial Matters Committee. Two of the men involved in that move were Harry Hughes and J. Joseph Curran Jr., the ticket that McGuirk and running mate Samuel W. Bogley will face in the Sept. 14 primary.

Hughes and Curran wanted Malkus out for ideological reasons, feeling it was time the Eastern Shore conservative be taken out of his position of power. McGuirk, who is conservative enough to have supported former Alabama Gov. George C. Wallace's candidacy during the 1972 presidential campaign, did it for more practical reasons.

"I did it to strengthen the city of Baltimore," he said. "I like Fred Malkus and I didn't enjoy it, but it put Joe Curran in a chairmanship and it helped make me vice chairman of Economic Affairs."

From that vice chairmanship, McGuirk spent the next eight years honing his Soft-Shoes image. He also had a brush with death when he was involved in a serious automobile accident in 1969. Driving home from a Senate session that lasted until 1 a.m., McGuirk fell asleep at the wheel. The result was an accident that left him in a back brace for four months, although he returned to the Senate floor (to a raucous ovation) three days later. The accident also cost him eight teeth and as a result he now wears a plate that causes him to speak with a slight lisp.

In 1974, McGuirk became the committee chairman. By 1978 he was considered the man most likely to succeed Steny H. Hoyer as Senate president. Hoyer ran for lieutenant governor on acting Gov. Blair Lee III's ticket. McGuirk supported that ticket. Early in the race, asked to assess Harry Hughes' chances, McGuirk uttered his most infamous and, in the minds of most, ill-advised words. "Harry Hughes' campaign," McGuirk said, "is a lost ball in high grass."

The lost ball went on to pull one of the more stunning political upsets in state history and McGuirk's chances for the Senate presidency were shattered. "I don't regret the statement," McGuirk said. "If it had been inaccurate, I would. But at the time, it wasn't."

McGuirk returned to his chairmanship, where he continued to be one of the legislature's dominant figures. "The Great Amender," he is called because bills tend to go into his committee saying one thing and come out saying another. And, legislators point out, McGuirk manages to make one think that he has saved your bill with his amendments.

"He has this way of calling you up and saying there are people who have problems with a bill and he's going to try to save it," said one legislator. "Then he calls back and says he's fixed it for you. Probably, no one had any trouble with the bill. But you end up feeling like you owe Harry McGuirk a favor."

Del. O. James Lighthizer (D-Anne Arundel), who is leaving the legislature to run for county executive, remembers the first time he testified before McGuirk's committee. "I was scared to death because I'd heard so much about McGuirk," he said. "It wasn't a very good bill, either. When I finished I got up to leave and McGuirk waved me over and whispered, 'do you want the bill?' I told him it wasn't a very good bill and if he couldn't fix it I wouldn't be upset if he killed it. He did kill it but I never forgot him asking me like that."

Many who have served with McGuirk admit to being torn by the prospect of a Hughes-McGuirk race. "The people of Maryland wanted an honest governor and they got one," said Sen. Thomas V. Mike Miller, head of the Prince George's Senate delegation. "No runs, no hits, no errors, that's Harry Hughes. But Harry McGuirk is living proof that the creator endowed ordinary men with extraordinary talent. He runs the Senate without getting credit for it."

In spite of such praise from his colleagues, the snickering was loud when McGuirk began telling people a year ago he was planning to run for governor. Even now, seven days before the filing date, some are still wondering what McGuirk is really up to. If he is running, they say, he is on a suicide mission: he won't get votes in Montgomery County, he won't raise enough money, he won't come across well on television . . . .

"Everyone thinks image will kill him, that he won't do well on television, but there are few things in this world Harry McGuirk hasn't been able to master," Devlin said. "Until we see him on TV, we shouldn't count him out." Valued Running Mate

McGuirk will not be on TV before late July. He and Bogley plan to file on July 2. Although Bogley was an outcast in the Hughes administration, lightly regarded by those around him, his presence on the McGuirk ticket is viewed as something of a coup for McGuirk.

"It gives him an added degree of credibility," Weisengoff said. "After all, if Sam Bogley, who is beyond reproach, says the man is honest and would be a good governor, how can anyone argue?"

Bogley, with his boyish good looks may balance McGuirk's slick old-pol appearance. "In 1970 when we ran as a slate in Prince George's Sam Bogley was our sex symbol," Miller said. "He might do the same for McGuirk."

McGuirk won't say whether Bogley will appear on his TV ads, but most expect he will. In the meantime, the campaign now appears serious, with McGuirk appearing all over the state, pushing his belief that the state needs "true leadership because the next four years are going to be very difficult."

Tuesday, McGuirk will hold a $100-a-person fund-raiser. He would like to gross $100,000 and he is hoping those who have lauded him as a legislator will at least stay neutral until he can establish himself as a candidate for governor. He is also hoping that Baltimore Mayor William Donald Schaefer, who seems to enjoy tweaking Hughes, will do so once again by appearing at the fund-raiser or at the official opening of his campaign headquarters this week in the city.

McGuirk very badly wants to be taken seriously and not be regarded as this campaign's lost ball in high grass. When he announced his candidacy on March 16, a story analyzing his chances appeared quoting Montgomery Sen. Victor L. Crawford as saying McGuirk could not beat Hughes. Reading quickly, McGuirk thought the speaker was Sen. Victor Cushwa (D-Washington). That evening, McGuirk motioned Cushwa off the Senate floor and into the men's room.

There, he demanded to know why Cushwa would say such a thing, why he would write him off so quickly. Cushwa pleaded innocent. Even when he realized Cushwa had not made the statement, McGuirk was angry. He does not like to be taken lightly.

Which is why on the night he introduced Bogley as his running mate, McGuirk walked out of the Stoney Creek Democratic Club beaming. The press had turned out, he and Bogley had been questioned at length and now, finally, it appeared people were beginning to believe he was running for governor.

"Now," he said softly, "they'll have to take me seriously."