Pell said he was not surprised Brown resigned as secretary.
Brown had always told colleagues that the post wouldn't be his career, Pell said.
Word spread through the VA system last week that Brown's calendar was clear after July 1, Pell said.
That day is scheduled as his last.
Brown actually stayed longer than Pell expected. Brown had said he intended to stay only four years.
His likely successor is Hershel W. Gober, deputy secretary for Veterans Affairs. Gober, 60, also is a Vietnam veteran and a friend of President Clinton's from Arkansas. He helped mobilize support among veterans for Clinton's 1992 campaign.
During his tenure, Brown boldly told lawmakers to cut other programs before coming after the Department of Veterans Affairs. He also succeeded in leading the agency away from its extensive network of hospitals toward a system of outpatient care for the nation's 26 million veterans.
Brown, 53, who lost use of an arm in combat in Vietnam, also secured funding increases of nearly $1 billion a year for the department at a time when all branches of the government were pinching pennies. With an annual budget of $41 billion and 215,000 workers, it ranks second to the Department of Defense among Cabinet agencies.
Some of Brown's success at obtaining funding for the VA is apparent at the Martinsburg hospital, where work was recently completed on a new emergency department with state of the art equipment, renovations in the out-patient department and construction on a new laundry facility.
Brown also was not afraid to make changes in the VA medical system to make it similar to private medicine, Pell said.
Brown instituted changes that have led to more veterans treated as outpatients instead of being kept in the hospital when unnecessary, Pell said.
Pell said he hopes President Clinton is able to replace Brown with another advocate for veterans.
"I'm sure the replacement will have big shoes to fill," Pell said.
``Serving in your Cabinet has been the high point of my life,'' Brown said in his resignation letter to Clinton, which also thanked the president for his support. ``Because of that support, I was able to be a secretary for veterans affairs, not a secretary of veterans affairs.''
In a reply, Clinton said he accepted the departure with deep regret.
``Your commitment to America's veterans reminds all of us of our great debt to those who have risked their lives, as you did, in defense of liberty,'' the president said.
The Associated Press contributed to this story.