Were any Americans ever under British command during WWII? Was Montgomery (or any other British officer) ever supreme ground forces commander?
US forces in the Med were under the nominal command of the theater commander Field Marshall Harold Alexander. However, operational control was by US officers at all levels of the echelon of command.
During the Battle of the Bulge all forces, including those of the US, on the north side of the bulge were temporarily placed under the command of Field Marshall Montgomery. Here again, Montgomery decided on the general placement and use of US divisions but operational details were up to the US division commanders.
Yes they were. Monty was the operational commander of all Allied ground forces for Operation Overlord.
But his boss was still an American.
Let’s not get carried away here. No British troops were under the direct operational control of US commanders either. Each nation had its own operational commanders starting with army commanders (two or more corps) down through corps commanders (two or more divisions), division commanders (two or more regiments), etc., etc.
In all cases there was an overall theater commander who had troops of all the allied nations in the theater and subject to his control. The ETO was under a US commander because by far the bulk of the forces there were US.
Although in theory this wasn’t planned (e.g. look at the 5 beaches in Normandy - strictly separate with two US, two British, one Canadian) for practical reasons it often happened, particularly at the junction between two armies.
For example, the records of the US 75th Infantry Division, which fought in NW Europe, often at the boundary between the US and British armies there, shows that it had British units (e.g. Lothians & Border Yeomanry, Fife & Forfar Yeomanry, 115th Infantry Brigade) attached to it at various points, as well as Belgian and Dutch units, and also had some of its 3 component regiments detached to British units (291st Regiment to the 6th Airborne Division, and so on).
The place where cross-national attachments happened the most is the Mediterranean. In Tunisia in 1942-3, the British 1st Army contained two British Corps (5th and 9th), and a US Corps (the 2nd) as well as a French one (19th). Conversely, the US 6th Corps landed at Anzio in Italy with one US division (the 3rd Infantry) and one British one (the 1st Infantry).
There are lots of other examples - both links above are from the Center for Military History - a good place to find details if you’re interested.
I also wonder about the China-Burma-India theater where resources were scanty.
I think maybe “command” is being used in two different senses here. One sense is when a unit from one country is attached to a larger unit from a different country, as attaching a specialized battalion to a regiment for some operation or other. Say a British Commando battalion to a US infantry regiment for a landing somewhere if a US Ranger isn’t available.
Abother meaning of “command” would be to have a US Captain put in as commanding officer of a British infantry company or vice versa. I don’t think that happened.
(nitpick) In US parlance, when an organization is referred to by number and type only, as in 82[sup]nd[/sup] Infantry what is (nearly) always meant is a regiment. When other groups are meamt. the type of group is specified. As in “82[sup]nd[/sup] Infantry Division; Company B, the 3[sup]rd[/sup] Battalion,” etc…[/nitpick]