More than any of President Carter's hirings and firings yesterday, the decision to drop Joseph A. Califano Jr. as secretary of health, education and welfare sent angry tremors through the Washington liberal establishment.

"It was like firing Mickey Mantle because he couldn't get along with the bat boy," quipped consumperphile Ralph Nader, in a reference to the newly emplaced caudillo of the White House staff, Hamilton Jordan.

Sen. Edward M. Kennecy (D-Mass.), the looming last hope of the liberal Democrats and the subject of the darkest White House political surmise, leaped immediately to Califano's side yesterday.

Speaking on the Senate floor during debate over the HEW appropriation bill, Kennedy said it was an "extraordinary irony" that when the nation's attention is focused on energy and inflation the first casualty would be the Cabinet member most concerned with "those unable to look after themselves," the millions of ill, handicapped and poor Americans.

There have been strong suspicions in the White House of a closet political aliance between Kennedy and Califano, despite differences on sensitive health policy issues. True or not, those suspicions are likely to become enormously self-fulfilling by the manner of Califano's purging from the administration.

The plaudits yesterday from the House and Senate sounded one consistent theme: the Cabinet member who seemed to have the best grip on his agency, the most ungovernable of them all, was the first to go by the hand of a president who asks "Why Not the Best?"

By Califano's own account, the president praised him deeply, but then explained that he was accepting his resignation for two reasons. One was the existence of a "personality conflict" between Califano and four high-level White House staffers, Jordan, press secretary Jody Powell, congressional liaison Frank Moore and budget director James T. McIntyre.

The second reason was that the president wanted to get his Cabinet in shape for the reelection campaign. By one authoritative account, Carter told Califano he would be a liability because powerful interest groups were antagonized by his stands on smoking, hospital costs and desegregation.

So impressed, nonetheless, did the president remain with Califano's abilities, according to well-informed sources, that he offered his HEW secretary a new job in the administration - the ambassadorship to Italy. Califano, who came to Carter's service from a $500,000-a-year law partnership, is reported not to have been tempted.

Although Carter campaigned for office against Washington's network of insiders, he reached high into that network after his election when he chose Califano for the HEW post.

Feisty, impatient and unabashedly abrasive, Califano quickly took the cudgel to the massive HEW bureaucracy and to the array of interest groups the agency regulates and funds.

"He communicated a sense of toughness," said one aide, "He says that because we run a social agency dealing in doing good doesn't mean we have to be soft."

Califano developed the reputation of a slave driver who built few personal loyalties other than the devoted circle directly around him - the very ones he drove hardest of all.

He came to work by 7 or 7:30 a.m., and stayed until 8 or 9 at night. He was unrelenting about dressing down subordinates in private sessions. Those unfavorable stories about his chef and his chauffeur probably gave satisfaction within the agency to those who had felt the lash of Califano's demanding drive.

Yet he did stir the huge federation of bureaucracies comprising HEW out of the defensive torpor into which they had fallen during the Nixon and Ford years.

On Capitol Hill, at the outset of his tenure in HEW, Califano displayed all the political grace and difficence of the class grind at a fraternity beer bust. He was viewed by conservatives and even middle-of-the-roaders as an advocate of Big Government and discredited liberalism.

Only in the past year had he begun to achieve a stronger sense of rapport with the barons of the Hill. But the capstone of Califano's legislative program at HEW, the hospital cost containment bill, still lies in the legislative mill after failing in 1977 and 1978.

In his departure statement yesterday, Califano permitted himself the most gentle of rebukes to the president.

"Much of what we began in these last 30 months, of course, is not yet finished. I can understand, hwoever, that the president could feel the need to reorient his priorities, to rely more heavily on his personal staff, and to prepare his administration for the challenges of the next 18 months....

"Inevitably, there will be those who will say, in trying to explain this event, that I made waves. I hope I did, but I will leave that judgment to you and to the passage of time...."

Califano took leave of his staff in an emotional farewell, one that left him for a deeply felt moment in a rate posture of speechlessness. CAPTION: Picture, JOSEPH A. CALIFANO JR...."personality conflict" cited