President Reagan today appointed John A. (Jack) Svahn, under secretary of health and human services, to be the chief White House domestic affairs adviser.

Svahn, 40, will be assistant to the president for policy development, overseeing the White House Cabinet councils.

Svahn, who will report to White House counselor Edwin Meese III, succeeds Edwin L. Harper, who resigned to take a job with a Dallas firm.

Svahn has been the second-ranking official at the Department of Health and Human Services since March, and served concurrently since May, 1981, as commissioner of Social Security. There had been rumors of friction between him and HHS Secretary Margaret M. Heckler.

In announcing the appointment today, White House spokesman Larry Speakes quoted Reagan as saying that Svahn "brings to the White House the broadest possible combination of theoretical background and practical program experience in coping with the most pressing problems of our time."

Svahn served on the Reagan transition team in 1980. Before joining the administration he was a consultant specializing in public policy management, according to a White House statement. He had served in Reagan's administration when Reagan was governor of California, and held posts in the old Department of Health, Education and Welfare