Marcio Novelli self-describes as alt rock pop.
That probably works. I have been trying to think of sounds I could compare him to and have not been having much luck. There is a plaintiveness to the vocals that reminds me a little of the Rejects and Boys Like Girls, but with a single performer it is quieter. It is not necessarily acoustic, but has that feeling. Songs tend to be more emotional and serious, which may be why the alt comes before rock and pop.
(Without being very familiar with his work, I think Ed Sheeran fans might like Marcio Novelli.)
My personal favorite was "This Song Is Not For You", which has a new fan participation video. Other good tracks to check out are "In The Mourning" which has a more complex instrumentation adding layers, and "Siren Song" which throws you right in with no intro, giving an interesting effect.
Music is available through iTunes and Amazon.