Maryland House of Delegates Speaker John Hanson Briscoe, who ruled the lower chamber with a sharp wit and a stern hand for the last five years, announced yesterday that he will retire from politics to devote more time to his personal life.

The St. Mary's County Democrat thus becomes the fourth and last member of the General Assembly's top echelon to vacate his position in recent weeks, opening the way for the first complete realignment of the legislative leadership in at least 10 years.

State Senate President Steny H. Hoyer has given up his legislative post to run for lieutenant governor in this fall's election, while Senate Majority Leader Roy N. Staten has also retired and House Majority Leader John S. Arnick is running for a Senate seat.

All four lawmakers owe their-political rise in part to now suspended Gov. Marvin Mandel, who could consistently rely on their help in getting his way with the legislature before he was convicted last August on political corruption charges.

"it's going to be a new era with new leadership," predicted Del. Gerard F. Devlin, a rising power in the Prince George's delegation. "For years, the shots have been called in the governor's office. Now the decisions will be made in the legislature."

Briscoe, 44, a low-key, courtly man known for his powers of persuasion and mediation, was credited with helping the legislature regain a large measure of independence at this year's session, the first under Mandel's successor, Acting Gov. Blair Lee III.

He played a crucial role in the shuttle diplomacy that led to the enactment of a property tax reform package, persuading Lee to give up a major portion of his proposal and accept competing measures pushed by legislative leaders.

"It was typical of John's success" recalled Del. Benjamin L. Cardin (D-Baltimore), who is considered the front-runner to replace Briscoe. "He had the ability and credibility to go to the governor and the legislative leaders to get a compromise."

If Cardin, a liberal Democrat and chief architect of the recently enacted property tax measure, became speaker, he would be expected to play a stronger role in a advocating legislation and would be more receptive to reform legislation than Briscoe, House members said.

powerful Sen. Harry J. McGuirk is the

On the Senate side, Baltimore's odds-on favorite to become presiding officer of the upper chamber. If he and Cardin both head their chambers, Baltimore will boast top officers in both houses.

During his five years as presiding officer of the sometimes unruly House, Briscoe rarely sponsored legislation, preferring instead to remain above the fray and retain the neutrality that allowed him to work out compromises on important bills.

"I've tried to blend the different philosophies of the House," he explained in an interview yesterday. "I always figured I could operate a lot better by not being an initiator. Once you do that you get too personally involved in a bill."

Standing in an upright military posture on the podium of the House chamber, he closely followed tortuous debates, correcting delegates when they defied legislative rules and often breaking tense moments with an infectious sense of humor.

While he was generally praised for his fairness in allowing all sides to argue their positions, he had little tolerance for floor demonstrations and was criticized by minority factions in the House for being too rigid in imposing the rules.

During a heated debate on the death penalty two years ago, he told a black delegate from Baltimore that he would have him physically removed from the House by a state trooper if he did not stop his harsh remarks and querulous behavior on the floor.

When a Montgomery County delegate attempted to block passage of the Baltimore convention center with a one-man filibuster in the final minutes of the session two years ago, Briscoe stopped him by invoking an obscure House rule banning dilatory tactics.

Among Briscoe's relatively few critics were the House liberals who found him too wed to tradition and too cool to reform legislation. Several years ago, at the end of a session, a Common Cause offical blamed him for being "the last stumbling block of reform" in the Maryland legislature.

Briscoe entered politics in 1962 when he was drafted by a reform slate to run against an entrenched county machine. After his victory, he quickly moved through the legislative system, and was named chairman of the Environmental Matters Committee in 1968.

In recent years, he complained of becoming tired of the job and twice tried unsuccessfully to obtain an appointment as a judge. He was so certain he would receive the appointment before the latest session that he had his portrait painted to hang on the emarbled House walls next to other past speakers.

Several Democrats have been nominated as possible replacements for House Majority Leader Arnick, including Del. Frederick C. Rummage of Prince George's County, Del. Donald B. Robertson of Montgomery County and Del. Tyras S. Athey of Anne Arundel County.

On the Senate side, Sen. Melvin A. Steinberg (D-Baltimore County) and Sen. Arthur H. Helton (D-Harford) have been named as contenders for leadership position.