How do I import an OBJ objects into a Blender file with their textures and materials intact?

I want to import an OBJ environment into the scene with the character already set with his textures and materials. Is there I way I can import the environment mesh without having to re-apply all the materials manually?

Try searching before creating topic. Check this:

Not with Cycles render active. The .mtl is going to set Blender render materials, and the two render engines aren’t compatible.

That is just wrong. Where did you get that idea?

https://en.wikipedia.org/wiki/Wavefront_.obj_file#Material_template_library

The .mtl doesn’t support pbr definitions, importing with Cycles active makes a messy compatibility tree for it and fails. Disabling nodes for the material makes it work in Blender render. Manual work is needed to get the materials set up.

The OP hasn’t provided test files, so “just wrong” it aint.