You still have a lot of places to explore. Don't toss the census you found but don't assume it's the right person either. Even people with unusual names will sometimes share them. If his name is the least bit common, there will be many others with the same name.
Do a careful look through Ancestry (if you don't have a subscription, your local library probably will). Record every fact (and the source). Even very minor things may turn out to be important. And you can use things like the address on one doc to confirm that the person you found on another doc is your family member.
Do Google searches. Surprising things come up. Use your library to look through newspaper archive sites. In addition to things like birth and wedding announcements and obits, there could be a news article about a family member. Go through online archives of the papers local to where your family lived.
Try to dig up his naturalization papers. NARA archives are awesome places (but they won't have the docs unless it's the same area as where he filed his paperwork) and they have free access to Ancestry and other sites too. Military docs are helpful too if you can find them.
Do you know where he was buried? If you can find the cemetery you can see or get a picture of the gravestone and you can also get info from the cemetery office.
Try to get vital records. They're in the municipal office of wherever the event happened. You probably can't get a birth cert if it was in Germany (well not easily). But try for death and marriage.
Keep searching those censuses, don't stop after finding one matching name. And check out city directories too.