Britain's Chief of Defence Staff, Admiral Sir Michael Boyce, is to retire from the post
Admiral Boyce was knighted in 1995
The former Chief of the General Staff, General Sir Michael Walker, will take over as head of all three armed services and the government's most senior military adviser on 2 May.
Admiral Boyce, 60, has spent only two years in the job and there had been reports he did not get on with defence secretary Geoff Hoon.
But defence experts said the post was normally held for only a relatively short time, and Admiral Boyce would be remembered as a good chief of defence staff and a "steady pair of hands".
Charles Heyman, editor of Jane's World Armies, said: "He's a cool, calm character. He gets on very, very well with his subordinates and also with his fellow senior commanders in the US."
He is slightly uncompromising, but... you need someone who will be unambiguous about the abilities and limitations
Rear Admiral Richard Cobbold, Royal United Services Institute
Rear Admiral Richard Cobbold, of the Royal United Services Institute for Defence Studies, said Admiral Boyce had had a "successful" time.
"It was remarkable because he fought two significant wars - Afghanistan and Iraq - in two years," he said.
He said during the war in Iraq, the main military part of which drew to a close just days ago, the admiral had demonstrated his ability in the key role as a "hinge" between politicians and the military.
Late last year Admiral Boyce hit the headlines after a spat with Defence Secretary Geoff Hoon over the handling of the fire strike.
Admiral Boyce had said he was concerned about the effect the strike was having on the armed forces, which risked being overstretched by covering for firefighters.
The Times newspaper said at the time the admiral's broadside was "as close to a mutiny as you could get in the British military establishment".
But Major Heyman said these kind of tensions were normal between senior defence staff and politicians - with politicians often wanting more from military chiefs than they were prepared to give.
And Rear Admiral Cobbold said such "constructive tension" was not a bad thing.
"He is slightly uncompromising, but at a time when British armed forces are about to be committed to battle, then you need someone who will be unambiguous about the abilities and limitations, and if occasionally it means saying 'no', then that's how it should be," he said.
Both men recalled the start of the war in Afghanistan, when Admiral Boyce was ridiculed by US defence secretary Donald Rumsfeld for saying troops would still be in Afghanistan the following summer.
"Of course, Admiral Boyce was proved absolutely right," they said.
Admiral Boyce could also take credit for increases to the Army budget during his tenure, Major Heyman said.
He also balanced the needs of the three individual forces and did much to bring the three forces together.
General Walker's appointment was announced last July.
The 58-year-old has been an officer for 36 years and served in Cyprus, Northern Ireland and Germany.
He is perhaps best known as the successful first commander of the multinational component of Ifor, which helped keep the peace in Bosnia.