JOHN Forbes Kerry is a man of ''many hobbies.'' He jogs, flies planes, bikes, skis, plays tennis, enjoys sailing, plays touch football, and makes model ships.
But in the coming months, the tall, rangy Massachusetts Democrat who is about to leave the comparatively quiet office of lieutenant governor for the less-tranquil US Senate, may have little time for such favorite leisure activities.
Government is his first calling, he emphasizes, terming his newly won Senate post ''the best job in the US.''
Approaching the Senate with almost-boyish enthusiasm, Mr. Kerry makes it clear that he intends to be his own man. Emphasizing his admiration for both senior Massachusetts US Sen. Edward M. Kennedy and Sen. Paul E. Tsongas, the man he will soon succeed, Kerry says he'll not be a carbon copy of either.
''Each of them has been very helpful to me,'' he states, adding that he expects ''there will be a very close working relationship'' with Senator Kennedy despite ''certain differences of approach to the economy and how the Democratic Party defines itself.
''Fundamentally, we want the same things for Massachusetts,'' he explains.
From an ideological standpoint, the senator-elect is closer to Senator Tsongas than to Kennedy. Still, both his style and his priorities are his own.
''I think Paul and I are very close on many issues. I agree with his views on the economy and the perception that the Democratic Party has to be much better at dealing with economic matters,'' says Kerry. ''But, at the same time, I think we can do that without losing our conscience and our basic concerns as a party for human needs.''
In other words, he eschews the current, unclearly defined label of ''neoliberal'' which has been applied to Tsongas and other new-generation Democrats in the Congress. Just plain, old liberal is good enough for him, Kerry indicates. He praises the retiring senator for having done ''a lot of good things'' during his six-year term, but adds that he was not elected to follow in Tsongas's footsteps, but rather to pursue his own course and ''be myself.''
Naturally, Kerry is grateful for the Tsongas gesture of relinquishing his seat, ''probably around the first of the year'' and several days before the new Congress convenes, so that Kerry can be appointed to the vacancy and thus grab a bit of an edge over some other newcomers. The move means being ''six or seven places up the seniority ladder'' over other newly elected senators, Kerry says.
As for potential committee assignments, Kerry notes that of the four major Senate panels the two that might be the most appealing to him are out of the question. Senator Kennedy is on the Armed Services Committee, and there are no openings on the Finance Committee. That leaves the Appropriations Committee and the Foreign Relations Committee, he says.
Banking; Housing and Urban Development; Commerce, Science, and Transportation; Environment; and Public Works are other senatorial committees of particular interest to the Massachusetts senator-elect.
While Kennedy is ''a national senator, with national responsibilities and an international reputation'' and Tsongas devoted considerable attention to peace efforts in Central America and social and economic problems of Africa, Kerry says he intends to be heavily involved in the problems and particular concerns of his home state and, initially at least, doubts he will become similarly involved.
Being ''sensitive and responsive to the needs of the commonwealth'' is very important, says Kerry, pledging to have ''a very strong Boston presence.'' Besides having an office in the Hub, he plans others in the southeastern and western parts of the state. ''About half of my staff will be in Massachusetts,'' he adds.
Kerry notes that both he and Senator Kennedy have specific areas of common concern, including strong interest in passage of crime-control legislation.
A major Kerry goal is to ''work closely'' with local officials like Boston Mayor Raymond L. Flynn. ''Ray and I got to be very good friends during my campaign. He was just superb,'' says the senator-elect.
On a broader horizon Kerry says, ''My hope is to be able to impact on policies relating to international concerns and expenditures. The way we are going to have more bacon to bring home is by having a world that is not expending as much on the military sector.''
The former naval officer, who first came to prominence in 1969 as national leader of Vietnam Veterans Against the War, is today no less committed to peace through arms control. That includes support for a negotiated nuclear-weapons freeze. Kerry also specifically voices concern for ''ending war in Central America and improving US relations with all of Latin America.'' The future of the Philippines is another of his prime concerns, he adds.
Educated at Yale University and the Boston College Law School, Kerry says he has been ''intrigued'' with the political process and the way government works since high school days. But it was not until 1970 that he gave the possibility of a political career much thought.
Kerry makes clear there was no political motive behind his antiwar activism, including testimony before a congressional committee. His goal then was ''to try to influence the process much as Ralph Nader and others were doing'' in behalf of various causes.
Like many elected officials, Kerry knows what it is like to lose. In 1972, after winning the Democratic nomination for the US House in the state's Fifth Congressional District, he was beaten by his Republican foe. But there never was any doubt among those close to the Massachusetts political scene that he would try again for some office.
After that defeat, Kerry went on to law school; moved into the Middlesex County district attorney's office, where he became first assistant; served as host of a radio talk show; set up a law practice; and became a weekly public-issues commentator on Boston's Channel 5.
Elected lieutenant governor two years ago as running mate to Michael S. Dukakis, he has had prime responsibility for state-federal relations. This role as the state's executive-branch ambassador to Washington has helped prepare him for his new job as senator.
The lieutenant governor's post will not be filled, but the main functions of the office will be handled by a senior member of the governor's staff.
And with his State House staff remaining virtually intact, Kerry says that, ''in a sense, this operation will be almost an adjunct of my Senate office.'' Such close ties, he suggests, will give him ''an advantage in working on the priorities for Massachusetts.''
Hailing the teamwork within the Dukakis administration and his part in it, Kerry credits the governor for having delegated to him important responsibilities, including that of membership on the acid rain task force of the National Governors' Association.
''This is a very important office when the governor is willing to utilize it and give the lieutenant governor key assignments, such as state-federal relations,'' Kerry asserts.
Getting elected to the Senate cost Kerry ''just short of $2 million'' and left him with a campaign deficit of ''a good, solid $375,000,'' he says. ''Obviously we will be fund-raising for quite awhile.''