Stanley Sporkin, the man who has been viewed as a thorn in the side of corporate America for his vigorous enforcement of federal securities laws, will leave his post of chief of enforcement for the Securities and Exchange Commission to become general counsel to the Central Intelligence Agency.

Sporkin, who led the SEC through a period of major enforcement activity, initially declined to comment on reports he would move to the CIA, now directed by former SEC chairman William J. Casey. Later, however, a spokesman for the CIA confirmed that the appointment will be made.

Sporkin is not expected to leave the SEC until next month. He resigns at a time when the SEC is being taken over by a new chairman, John S. R. shad. Sporkin said he has "great, great faith in this new guy." Shad would name Sporkin's successor.

Sporkin joined the SEC in 1961 as an investigator. He was named director of enforcement in 1974 and oversaw some of the agency's best-known investigations, including revelations about bribery by American corporations abroad that led to adoption of the Foreign Corrupt Practices Act. In 1978 he received the Rockefeller Public Service Award. Some of his efforts include the agency's investigations into the dealings of financier Robert Vesco, payoffs in Honduras by United Brands and payoff schemes involving Ashland Oil and Northrop Corporation.

During the Nixon administration then-chairman Casey repeated to Sporkin a request by former Commerce secretary Maurice Stans not to push for testimony from Vesco's secretary, who knew of a $200,000 contribution to Nixon that would be "politically embarrassing."

According to news accounts, Sporkin refused and later testified that he told Casey, "Someday you are going to be thankful for relying on my judgment on this matter." Sporkin, whose colleagues at the SEC describe him as "tenacious and full of integrity," said he believes the agency's enforcement activities will not be harmed by his departure. "Any kind of program that's going to be effective has to be vigorously enforced. I hope it will continue to be so; otherwise it won't be worth much," he said.