After four decades at the forefront of the chamber’s legislative battles, House Parliamentarian Charles Johnson plans to submit his resignation this week, according to leadership sources on both sides of the aisle.

On Tuesday, the House GOP leadership signed off on current Deputy Parliamentarian John Sullivan’s elevation to the top post. Johnson will submit his formal resignation Thursday, and an official announcement and floor resolution paying tribute to him are anticipated the same day. Sullivan will take over the position at the end of May.

“Everybody really respects Charlie,” said a Republican leadership aide. “His leaving is a real loss to the institution, but everyone has confidence in John Sullivan.”

Congressional leadership sources said Johnson, who turned 65 in February, initially hoped to vacate the post earlier this Congress, but Speaker Dennis Hastert (R-Ill.) asked him to stay on until a replacement was chosen. Johnson agreed to postpone out of deference to the Speaker, those sources said.

“It makes sense” to wait for a replacement, said one Democratic leadership aide. “You don’t want a change-up in this position at this point. It’s a sensitive position, and you like to have consistency.”

The Parliamentarian is often at the center of partisan battles, and it is vital for the occupant of the post to maintain the trust of both Republicans and Democrats. Over the years, according to Members and aides, Johnson was able to do exactly that.

“He will be missed by Members and staff on both sides of the aisle,” said a Democratic leadership aide. “Charlie Johnson is a legend in the House. He is not only an expert, nonpartisan adviser on all things parliamentary, he also has sound judgment and rock-solid integrity.”

Even as he maintained good bipartisan relationships, Johnson’s position in the eye of the storm meant that he couldn’t always avoid controversy.

In 1996, Republicans and Democrats engaged in a testy war of words after the GOP successfully blocked a vote on raising the minimum wage. That maneuver was made possible by a ruling of the chairman that a point of order raised by a Republican against a Democratic motion was proper.

After Democratic complaints, Johnson wrote a letter to then-Rules ranking member Joe Moakley (D-Mass.) and admitted that he had erred in ruling that the GOP point of order was allowable.

Through it all, Johnson has been a steadfast stickler for the rules and traditions of the House. In 1999, for example, he asked Hastert to remind Members that they may not use cell phones on the chamber floor.

Johnson joined the Parliamentarian’s office soon after receiving a law degree from the University of Virginia in 1963. He earned a bachelor’s degree from Amherst College in 1960.

Sullivan served as the assistant Parliamentarian when Johnson was the deputy. He earned a bachelor’s degree from the Air Force Academy in 1974 before moving on to get a law degree from Indiana University in 1977.

Sullivan’s elevation from deputy to the top parliamentary post follows a long tradition of succession. Johnson served in the office for 30 years and became Parliamentarian in 1994 when William Brown retired from the post. Brown himself spent 20 years in that position after 16 as the deputy.

When Brown passed away in 2001, Johnson gave a statement that provided a window into his own thinking about the role of the Parliamentarian.

“William set the standard for the way, I believe, the office should run,” Johnson said at the time. “He thought the office should run on intellectual vigor, sharing of information and a sharing of responsibility with a grace that was accompanied by total devotion to the House of Representatives.”