leave him outside

Teach him how to use a litter box

Get a dog. You can actually teach them stuff.

>>2113591
Keep it in a crate.

Crate training doesn't work on cats, but it will only be able to shit and piss in the crate until it dies.

http://www.aspca.org/pet-care/cat-care/common-cat-behavior-issues/litter-box-problems

Could be the box isn't clean enough, some cats are really picky. I was having trouble with my cat and I thought it might be that so I made sure it never had a drop of piss or shit in it. The cat started using the box from then on and I never had a problem with her pissing on furniture

is it neutered?

>unloaded kitten in front of the litter box when I first brought her home
>she hasn't had a single accident in the ten years since

Is this normal, or did I just luck out?

>>2114197
Normal

>>2114197
That's pretty normal. Litterbox problems are fairly common in cats but 99% of the time are prompted by a specific situation, e.g. human thinks it's acceptable to only scoop the box once a week, human brings in a new animal and there's stress/territorial issues, urinary tract infections.