Depends on who you asked at the time. The disciples called Him "Rabbi," and He was asked to read and/or teach in a synagogue on several occasions. People also came to Him with disputes on matters of Jewish law--often to try to trap Him ("Is is lawful to heal on the Sabbath or not?"), but sometimes with genuine problems. But the Sanhedrin wasn't able to charge Him with anything until they asked Him straight, "Are you the Christ, the Son of the Blessed One?" He answered yes, which they considered blasphemy (hence the Crucifixion). It took another twenty years or so for most people on both sides to begin viewing Christianity as something other than just a Jewish sect, and the process of separation continued well into the second century.
*Now,* however, I think the standard position among Jewish religious leaders is that Jesus was at best a good teacher, at worst a false prophet, but definitely not Messiah. But then there are Messianic Jews who do believe that Jesus is Messiah but still keep kosher and adhere to traditions as they were in the first century (at least according to the ones I've met).