I am not sure what you’re getting at.
Yeah, I looked up the highest UK rank, FM. And there are A LOT of them, so not really any pure leader. But I’d think he’d be the top, if not in more recent times Montgomery, but he’s quite controversial. An alternative title is C-in-C/CGS/CIGS/CGS, of which I think Arthur Wellesley is still up there.
Since the monarch (King, Queen, Lord Protector) has regularly led the military in the past, I don’t think you can get higher.
That probably applies to Canada and Australia too.
This concept of generalissimo might be of interest here:
General of the Armies was created before General of the Army. Pershing was “General of the Armies” after WWI, but held it as a senior version of the four-star rank. When the regular rank of “General of the Army” was established during WWII, it was considered a five-star rank equal to European field marshals. Toward the end of the war, it was ruled by the War Department that Pershing’s rank was senior to the five-star ranks. George Washington was posthumously promoted to this six-star rank in 1976 as part of the Bicentennial stuff.
Except that I just learned that there were prior versions of both ranks, created after the Revolution and the Civil War.
After the American Revolution, the U.S. had no military rank higher than Lt. General (3-star). In 1799, Congress created the rank of “General of the Armies of the United States” to replace the title of Lt. General, but it would have remained a 3-star rank, as the army was small and had no officers higher than Maj. General (2-star). It was never actually given to Washington (the intended recipient) or any other officer.
Between the Revolutionary War and the Civil War, the title of Commanding General of the United States Army was held by the senior Maj. General. Winfield Scott, during his tenure as CGUSA was brevetted to Lt. General. When Scott resigned this post during the Civil War, the office of CGUSA was occupied by two Maj. Generals until U.S. Grant was promoted to Lt. General (only the third in our history at that point) and CGUSA. Post-war, Congress created the rank of General of the Army of the United States for Grant as a 4-star rank. There would only be one officer of this rank at a time, and Grant was succeeded by Gen. Sherman and Gen. Sheridan. The position was not filled after the death of Sheridan, and CGUSA was held by two Lt. Generals until the creation of position of Chief of Staff of the Army in 1903.
The in the inter-war years, as the Army shrank, the rank of Lt. General fell into disuse, and various Maj. Generals were Chief of Staff until US entry into WWI in 1917. During this mobilization, the rank of full general (4-star) was created for Pershing (as commander of US forces in Europe) and Tasker Bliss (as Chief of Staff for an enlarged Army). Post-war, Pershing was awarded the rank of General of the Armies of the United States in recognition of his services, with the understanding that it would be senior to the rank of General, even though all 3- and 4-star generals reverted to their permanent ranks of Maj. General. Though superior to regular generals, his insignia remained four stars, only in gold.
During WWII, the Rank of General of the Army was created to give to theater commanders who were in charge of supervising multiple 4-star generals. This rank also placed American officers on-par with European Field Marshals. Because Pershing was still alive, the media raised the question of where his “plural” rank stood in relation to the “singular” rank of the 5-star generals. The War department ruled that Pershing’s rank was superior, in effect a six-star rank. The six-star rank was to be re-introduced for the commander of the invasion of Japan, but that never came to pass.
In timeline form:
1799 - General of the Armies rank created as a three-star rank, never used.
1866-1888 - General of the Army granted as a four-star rank.
1919 - General of the Armies granted as superior to the four-star rank by an unspecified amount.
1944-1945 - General of the Army created as a five-star rank, General of the Armies confirmed as a six-star rank.
In Nazi Germany, Hermann Göring was the only man who held the highest military rank, Reichsmarschall.
I wouldn’t think so. First, the monarch has never personally led Canadian armed forces. Second, while the monarch is the commander-in-chief, that is a civil position, akin to the CinC status of the US president. If being CinC is the highest rank, then Washington is not the highest ranking officer; the President is.
That doesn’t seem to match the OP’s question, which is focused on the highest actual military officers.
Well, at least no one can say that this question was posted in the wrong forum 
Still dead.
Plus in general, Generalissimos aren’t placed above “all soldiers in the country, ever”, just current ones (either in the whole armed forces or in a subsection of it, the name was originally used for the Super Mega Head Honcho of a given multi-force army such as the Christian forces in Lepanto).
Super Mega Head Honcho would be a great military rank, BTW
Army Air Force and then just Air Force, right? Not Navy.
Would require a whole bunch of stars on shoulders and feathers on caps, mind you. At least one red ostrich plume. Turbans are good for that, you can put all sorts of stuff on a turban.
Oops, yeah typo repetition from Dewey.