For much of his professional life, the Rev. John Richard Keating has been trying to sort out the tangled lives of men leaving the Roman Catholic priesthood.

But the doubts of these men and the crises of the church in the past 20 years haven't fazed the man who on Thursday will become the second bishop of Arlington.

"I never had a crisis of faith," Keating says from his church-owned apartment in the local parish in LaGrange Park, Ill., a comfortable middle-class suburb of Chicago. "I never had an identity crisis. I never had any loss of esteem for the priesthood." He makes the affirmations more in wonder than in triumph, and jokes, as he recalls the post-Vatican II turmoil of so many priests: "At times I began feeling left out."

For the last few weeks, Keating, 49, has been saying goodbye to Chicago, the city where he was born and grew up and where he has spent his 25 years as a priest--with time out for specialized studies in Rome--assigned to a variety of bureaucratic tasks in the massive Archdiocese of Chicago.

He has held the chief administrative role of chancellor of the 2 million-member Chicago archdiocese and was archdiocesan administrator in the interim between the death of Cardinal John Cody and the installation of Cardinal Joseph Bernardin. But Keating says the role he most cherishes is that of parish priest.

"The highlight of my week, week after week, is to get into the pulpit, giving a little reflection on the scripture, meeting the people after mass," he says. Like most church bureaucrats, Keating has lived in various parishes of the archdiocese, helping out with parish duties on weekends.

"Being around the kids--I go swimming with them, play baseball with them, what you always think of a priest doing," he says, laughing at the Bing Crosby-like "Going My Way" image he has painted. "I just enjoy being in the parish," he says. "That's the compensation. And preaching . . . that's the biggest compensation."

When Keating is installed as bishop of Arlington this week, he becomes the absolute authority of a diocese of 188,000 Catholics in 21 counties of Northern Virginia. Yet there is no course of study, no clear-cut guidelines for what a bishop is supposed to do. "They call you on the phone and say, 'Will you go to Arlington?' and that's it," Keating says.

In practice, he adds, bishops learn their job from other bishops. "I'm not part of the fraternity yet," he says, "but they all send you congratulatory letters. I get the impression they are quite close."

Bishops are selected and assigned by the pope, usually on the recommendation of the Vatican's apostolic delegate in Washington. For those who understand the subtle nuances of Roman Catholic Church politics, Keating's elevation was reportedly foretold last August in the lavish praise voiced by the apostolic delegate, Archbishop Pio Laghi, for Keating's record as an administrator in Chicago.

His admiration for Cardinal Bernardin, known throughout the church for his skill as a conciliator, is apparent. "Here I am, front row center, to see how this man functions, how he's bringing the priests together," Keating says. "We're so proud of him. What a great schooling. It's been really a treat, a special grace. I'm sorry to be leaving. It's the beginning of a golden era here."

As bishop of Arlington, Keating will have need of his own skills in conciliation. His predecessor, Bishop Thomas J. Welsh, pleased many but alienated others in the diocese with his conservative outlook. Controversies in several Northern Virginia parishes continue to fester.

Keating acknowledged that partisans for one viewpoint or another have lost no time in trying to enlist him on their side, even though "I'm not even bishop yet," he says.

A tall, trim man whose face is creased with laugh lines, Keating sidesteps efforts to label him liberal or conservative. "My top priority is to find out the lay of the land," he said. "I want to be accessible, to be present when I should be present, to be a support to the people . . . As I approach ordination, I just pray that I have the wisdom for the task and that the people are not afraid to point out things to me." Keating will start by getting to know the Arlington priests "on a one-to-one basis," he says.

He has scheduled informal gatherings at four locations in the diocese next week so, he says, "the installation will be seen as reaching out to everybody. I want to be perceived as one who cares."

Keating, who made the decision to be a priest when he was about 12, says he faces some serious studying on the social justice issues that the American Catholic hierarchy is addressing. "I have very little experience being identified with that sort of issue," he says. "I'm just going to have to learn."

He will need schooling too, he says, in developing working relationships with members of other faiths. "The Chicago archdiocese is so large that you have an expert to handle that," he says. He's already accepted one invitation to an ecumenical gathering in Northern Virginia, he says.

Keating does not talk much about the turbulent Cody era in the Chicago archdiocese, dismissing those days with a sardonic smile, a shake of the head. He speaks of it obliquely in terms of "commitment . . . When I was assigned to Chicago under Cardinal Cody, I was committed to the church in Chicago. Now I am assigned to Arlington, my commitment is to the church in Arlington . . . My loyalty is to the church, to its teachings, to its goals."

The church, after all, is "not going to fall apart. It's going to have its bad days. But if you wait long enough, it's going to have sunny days."