John Lenczowski, 32, a political scientist formerly on the State Department staff, has been named the National Security Council's specialist on Soviet and east European affairs, succeeding Harvard professor Richard E. Pipes, according to White House officials.

Lenczowski is a Ph.D graduate of the Johns Hopkins School of Advanced International Studies. He was a staff member of the American Enterprise Institute and an aide to Rep. James A. Courter (R-N.J.) before becoming an adviser on the staff of Lawrence S. Eagleburger, undersecretary of state for political affairs.

Lenczowski is the son of George Lenczowski, a prominent Polish-born expert on Middle East affairs, who is a professor at the University of California at Berkeley. The younger Lenczowski, although concentrating on Soviet studies, has never been to the Soviet Union.

Among the new appointee's publications is a recent book, "Soviet Perceptions of U.S. Foreign Policy" (Cornell University Press), which argues that the Soviet Union sees the United States as having weakened during the 1970s, especially in the political and ideological area.

An article by Lenczowski, "A Foreign Policy for Reaganauts," in the fall, 1981, issue of the Heritage Foundation's "Policy Review" argued that "the greatest national security threat to communist leaders is an ideological one."

In view of this, he wrote, "what is needed is an ideological offensive" in which the United States espouses political values and capitalist market economics.

In his State Department post, Lenczowski played a role in developing the administration's "democracy initiative," which seeks to challenge the Soviet Union in the political field.