My grandfather enlisted in the US Army in 1942.
How can I find more details about his service?
Service records for those who served during the 20th century are held by the National Personnel Records Center, Military Personnel Records (NPRC-MPR) (part of the US National Archives in St Louis).
Records are turned over to the National Archives after a certain period of time -- this is sometimes called a a rolling window. For military records, they become archival 62 years after the veteran separates from the military.
At the time this answer was written, the current completed calendar year was 2016, so the cutoff year for accessing the records by the public is 1954. For Army records (including Army Air Corps and Army Air Forces), the page on Official Military Personnel Files (OMPF), Archival Holdings says we can access files for the following date ranges:
- Enlisted discharge dates 1912 to 1954
- Officers discharge dates 1917 to 1954
As each calendar year goes by, the end date will increase by one -- so when the current complete year is 2017, the end of the date range will be 1955, and so on.
However, not all OMPFs for Army veterans are available, because of the record loss during the fire which took place on July 12, 1973.
The instructions on how to order records are here: Official Military Personnel Files (OMPF), Archival Records Requests. If your relative's file was burned, NARA can supply some information from the other records held in St Louis (for an overview of the records they hold, see Bryan K. McGraw's presentation from the 2915 Virtual Genealogy Fair, listed below in the Resource list).
If you are starting completely from scratch, you may not have enough information to fill out the request form for the NPRC. Start with home sources and ordinary genealogical research to gather more information. The FamilySearch Wiki article on finding your WWII veteran (see below) has some guidelines for places you can look for information.
If you don't have any home sources that tell you the service number, gather as much information as you can, in case you need to distinguish your relative from someone else with the same name.
One tip from the FamilySearch Wiki article is to see if you can find their DD-214 (separation form) locally:
If you know a serviceman's hometown, inquire about his discharge papers at his county recorder's office. Servicemen were asked (but not required) to register their separation form DD-214. This paper gives their rank, unit, service number, separation date and place, birth date and place, physical description, pay, assignments, and awards.
If you can find the DD-214 locally, that will save you a lot of time, since it might take the NPRC a long time to answer, especially if the veterans OMPF was burned and they have to pull information from other files.
Special caution: if you find your relative's WWII Draft Registration card, that is not proof of military service. Just as you can be called for jury duty, and go to the courthouse as part of a pool of potential jurors, but not be selected to sit in the jury box, your relative was registered for the draft, but he may have not have served. For more information about the WWII registrations and whose records might be found there, see Judy G. Russell's post "Liable for Training" posted Jul 14, 2015 on her blog The Legal Genealogist.