Breed would be domestic short hair. Most cats are domestic cats of no specific lineage. The idea of there being such a thing as a purebred cat is relatively new and there just aren't that many cats who are purebred anything or from anything purebred.
His looks are due to coat pattern/colod and the colorpoint gene. While the colorpoint gene does come from the original Siamese, the gene is very widespread and pops up seemingly randomly when two carriers of it have a kitten. This guy is specifically a lynx colorpoint, meaning he has tabby stripes. I am not good at specific color within colorpoint so I will leave that aspect to someone else. If he didn't have the colorpoint gene he would be a tabby cat either brown or grey.
Summary, coat pattern is lynx colorpoint while breed is domestic shorthair.
I would describe the kitty in the picture as a seal lynx point domestic shorthair. Most cats are not any particular breed. Seal lynx is the colorpoint version of brown tabby.
He is, indeed, very cute and lutece is right about "seal lynx point" -- we have one and she's a wonderful cat! (I think lynx mixes have very expressive faces...)