He learned to love the spotlight as a boy soprano on the vaudeville circuit when he was 10; he went on to become internationally known as a pastor and evangelical opinion maker.

Now, at the climax of his career, he operates out of a bleak, one-window cubbyhole of an office that he shares with a secretary. But as chaplain of the Senate, the Rev. Richard C. Halverson has one of the most exclusive congregations in the world.

At Fourth Presbyterian Church in Bethesda, where Halverson, 65, will wind up 23 years of ministry at the end of this month, he preaches to upwards of 1,500 people every Sunday and directs a complex seven-day-a-week program that reaches around the world.

As the 50th chaplain of the Senate, he completes in a minute or two the only task that is specifically assigned him -- opening each session of the Senate with a prayer; often he is lucky if half a dozen of his distinguished parishioners are in the chamber to hear it. That doesn't worry him. "I pray to God for the Senate," he reminded a visitor.

Though still feeling his way through what his new job entails, Halverson sees it in much broader terms than the daily prayer, and his new parish as extending well beyond the 100 elected officials. "I feel, as the chaplain, I must be like a pastor to the senators, their families and staffs, to just be a faithful servant to all these people, to the [Capitol] police, to the people who work in the cafeteria, to the women who clean."

Most of them, he recognizes, have their own pastors, their own church connections -- at least those who want them. "So my role is to just be here, to be available to them, to be a servant of the public servants, to love them," he says after two months on the job as the successor to the Rev. Edward L. R. Elson, a Presbyterian who served for 12 years.

Throughout the nation's history, men from eight Christian denominations, including one Roman Catholic, have served as official Senate chaplains. Apart from the required opening prayer, the job has been pretty much what each man has made of it.

John Brackenridge, a Presbyterian, used the position in 1814 to thunder against the senators for legislation that he felt would lead to desecrating the Sabbath, such as transporting the mail. He warned that God would punish them, that "your temple and your palaces will be burned to the ground."

Two weeks later when British troops torched the White House, Brackenridge declared it to be "the chastening of the Lord."

For others it has been a graceful way to close out a career, as it was for Unitarian Edward Everett Hale, who had written "The Man Without a Country" 40 years before he assumed the chaplaincy.

In Halverson's case, his career in the public eye began early in Pingree, N.D., where he grew up. Possessed then by what he calls "a penchant for entertaining," he used to stand outside the pool hall and sing for nickels. His parents were divorced, but his mother "was very ambitious for me and she got me a contract with a vaudeville troupe that was touring Canada."

His show business career lasted only six months, because his voice changed. But from then on, the only thing he could think of was Hollywood. He got his chance the summer he was 19, when his other let him stay on and seek his fortune there after a family vacation in California. He lived on the 50 cents a day he earned working in a tiny auto-polish factory, and entered every amateur contest he could find.

Then came Christmas, his first away from home and family, and a deep loneliness compounded by an uneasy conscience. Even though his family had never had anything to do with churches, the life style he was drifting into in his pursuit of a show business career began to conflict with the strict moral code his mother had imparted.

With some qualms, he decided to attend a New Year's Eve service at a little Presbyterian church. "I had a very dim view of churches and pastors," he says. "In my view then, a minister was a man who had failed at everything else."

That service only reinforced his low opinion, and the minute the service was over, Halverson fled. But he was met at the bottom of the steps by a layman who welcomed him, introduced him to some other young men in the church and invited him to a breakfast the young people were having. When they discovered he loved to sing, they signed him up for the choir.

Bit by bit, the youth got drawn into the activities of that congregation, although he still hadn't changed his opinion of churches or pastors. But then came a young pastor fresh out of the seminary. To Halverson's amazement, the young minister, the Rev. David L. Cowie, was everything Halverson thought a man ought to be, shattering many of his prejudices about the church. "There was something about him that I wanted," Halverson recalled.

So on a Sunday night 45 years ago -- Halverson still marks the anniversary -- he had a serious talk with Cowie and concluded that the "something" he lacked was a commitment to Christ. "I gave my life to Christ. . . . I actually signed my life over to Him in a kind of deed. I still carry it around in the back of my Bible."

After finishing Wheaton College and Princeton Theological Seminary, Halverson served churches in California for a dozen years. He came to Washington in 1956 to work with the international prayer breakfast movement, a tie that he retained when, two years later, he was called to Fourth Presbyterian Church, which had just moved out from 13th and Fairmont streets NW to a new suburban site on River Road in Bethesda.

There were about 500 members when he arrived; now the church has 2,100 members, coming from as far away as Manassas and the suburbs of Baltimore, and three full-time pastors. The two Sunday morning services became so crowded last fall that the pastors launched an 11 o'clock Bible study class in the Kenwood Country Club across the street that draws about 300 each Sunday.

Though Fourth Presbyterian has become a shining light in worldwide evangelical Protestantism under Halverson's leadership, he has put down even deeper roots in the prayer breakfast movement that commands the loyalties of hundreds of men and women on Capitol Hill. The movement shuns publicity; one of its strengths is that the prayer groups have been one of the few places in Washington where men and women normally in the spotlight can admit their human and spiritual needs without fear for their public image.

Because of his association with the movement throughout his 25 years in Washington, as well as his friendship with the large numbers of men and women from Capitol Hill who attend his church, Halverson already has a wide circle of friends in his new parish.

In welcoming Halverson to the Senate on his first day, Sen. Mark Hatfield (R-Ore.), who was once a member of his congregation, called him "supremely suited to be our pastor and friend for the challenges ahead."

For all his youthful fascination with show biz, clergyman Halverson today functions more typically in quiet conversations, encouraging and motivating others to take the lead. "He has a style of leadership which evokes leadership in others," said the Rev. Dr. Edward White, head of the National Capital Union Presbytery.

White, who uses words such as "authentic," "unassuming" and "loyal" in characterizing Halverson's ministry, remarked that very often among clergy, "big-steeple preachers have big-steeple egos. Dick is uncharacteristic in that respect. . . .

"There's one thing I've noticed when I've been with Dick in informal gatherings. . . He will get to talking about other people and he talks about them in such a way that you'd think they'd hung the moon. He has such a tremendous appreciation for other people."

Halverson does not see his new parish as a recruiting ground for his own brand of Christianity. "I am here as a servant of public servants. My role is to love them, to be available to them, to try to stay out of their way and to minister privately to them as they come to me in need of my services.

"Of course, I believe that the ultimate answer to their needs is Jesus Christ, but I'm not going to hit them over the head with it," he said.

Halverson has promised he will reject any temptation to use his position to bring pressure for a particular piece of legislation. "I would not take any initiative to lobby," he said.

All of this fits with the more recent tradition of the post, which is supposed to be free from political influence. Under present rules, the chaplain is nominated by the majority party and elected for an indefinite term by vote of the full Senate.

The chaplain's office is a former storage room, about 9 feet by 15 feet, just inside the door of the Russell Office Building. Sharing the cramped space with his secretary scarcely offers Halverson a setting for the counseling he sees as part of his job," a visitor reminds him. "Well, I can always go where they are," he says with a laugh.

And the job does have its compensations. The chaplain's prayer leads off each day's issue of the Congressional Record. Halverson prays, in fairly workaday speech, for God to give his flock attributes such as strength, wisdom, humility, courage and divine protection from "the forces which would exploit . . . as pressure from interest groups builds." He is not given to flights of ornate language or great literary display.

Halverson writes his prayers a day ahead, and while he tries to keep them nonpartisan, he also strives for relevance."I pray over my prayers," he said. "I read the papers to see what's going on."

With the fast movement of events, he writes a goodly number of prayers that may never get used before the Senate. "But," he says, "they may be more important than the ones that are used."