William J. Casey has had his scrapes with congressional investigators before. He has also, as he pointed out yesterday, "been confirmed by the United States Senate four times."

The shambling, plain-spoken New York lawyer made plain that he has every expectation of being confirmed again, this time as director of the Central Intelligence Agency in the Ronald Reagan administration. Amid calls for more emphasis on covert action abroad and a more prescient intelligence system at home, Casey would be returning to a routine he left behind in World War II.

And the objections that were raised against him nearly 10 years ago -- when President Nixon named him chairman of the Securities and Exchange Commission -- could, as they did then, prove as much as an asset as an obstacle to speedy Senate approval. Casey was accused by critics then of too-sharp dealings in the business world. His supporters replied that they were impressed by his "energy and toughness."

Born in Elmhurst, N.Y., in 1913, Casey has always had a reputation as a quick study, a pragmatist interested in results. The kids he grew up with called him "Cyclone." Colleagues say he has no patience for perfect solutions. For Bill Casey, workable answers are much better than perfect ones.

A graduate of Fordham and St. John's University law school, Casey joined the Navy after Pearl Harbor, but found himself consigned, because of poor eyesight, to the tedium of procurement contracts. He managed to get close to people who were close to William (Wild Bill) Donovan, head of the Office of Strategic Services, and won a transfer to the OSS.

"As a man who had learned early how power functions," historian Joseph E. Persico has written, "Casey knew that in OSS most power lines led back to the Donovan law partnership in New York."

He was soon sent to London where he became chief of secret intelligence for Europe, with direct responsibility for penetrating Nazi Germany with secret agents in the closing days of the war.

After postwar service in Washington with a Senate committee and in Europe as a Marshall Plan adviser, Casey returned to New York, where he made a fortune practicing tax law and writing specialized and reportedly highly profitable manuals on tax, real estate and investment law and related subjects. Among the titles: "How to Raise Money to Make Money," "How to Build and Preserve Executive Wealth" and "How Federal Tax Angles Multiply Real Estate Profits."

Casey made an unsuccessful run for Congress in 1966, and was quoted as saying: "I've made all the money in business that my family could ever spend . . . I want to do something more meaningful and I'm convinced that with my qualifications, I can make a real contribution in public office."

An active Republican and contributor to conservative causes for years, Casey came in for his first Senate confirmation clash in 1969, when President Nixon named him to the advisory council of the Arms Control and Disarmament Agency.Chairman J. W. Fulbright (D-Ark.) of the Senate Foreign Relations Committee took issue with a controversial advertisement on behalf of the antiballistic missile system that a committee Casey founded had placed in various newspapers. But the committee approved his appointment.

A tougher battle developed in 1971 over his SEC appointment. The Senate Banking Committee quickly approved the nomination, but Sen. William Proxmire (D-Wis.) led a fight to reopen the hearings after a variety of lawsuits came to light.

In two of the suits, Casey was accused of violating securities laws. In another, which he eventually settled for $20,500 as part of a post-trial arrangement that included sealing the record, he was sued for plagiarism.

Casey's account of the plagiarism suit was disputed by the trial judge on several key points, fueling doubts about Casey's candor, but the committee stood behind his appointment by a vote of 9 to 3. Proxmire complained in a Senate floor speech that he still did not feel Casey sufficiently "beyond reproach" to be SEC chairman, but no one voted against confirmation.

Casey won high marks for his nearly two-year performance at the SEC, surprising many observers with the vigorous way he dealt with the securities industry. He restructured the stock markets to increase competition and strengthened financial disclosure laws to make them more "realistic."

The performance seemed to validate the predictions of some senators that his "rough-and-tumble background" would prove an asset at the SEC.

In October 1972, however, Casey became embroiled in a protracted and bitter dispute when the SEC turned over to the Justice Department its entire file -- 34 cartons -- on the International Telephone & Telegraph Corp. ITT had been accused at Senate hearings earlier that year of pledging financial support for the GOP national convention in return for settlement of antitrust disputes with the Justice Department.

House members who had been seeking some of the records for congressional scrutiny called the SEC move an effort to put the documents out of reach until after the 1972 elections. Casey insisted that he gave the Justice Department the files because the department had asked for them.

At hearings in 1973, however, the No. 2 man in the Justice Department, Ralph Erickson, testified that he took the file under pressure from Casey and John Dean, then White House counsel.

Casey, by then undersecretary of state for economic affairs (after his third confirmation hearing), defended his actions, declaring that names in the ITT file could have been "politically useful" to opponents of the Nixon administration and that possible leaks from the SEC could have jeopardized any criminal prosecutions.

Casey left the State Department in 1974 to become president of the Export-Import Bank (his fourth confirmation hearing), a post he held for two years. He returned to practice law in New York with the firm of Rogers & Wells and joined the Reagan campaign as its campaign director last February.