For an alias to work in ~/.profile the session needs to be a login shell. Bash, which is probably what you're using, is typically read from ~/.bash_profile.
There's a good explanation of the differences mentioned here:
http://superuser.com/questions/183870/difference-between-bashrc-and-bash-profilehttps://superuser.com/questions/183870/difference-between-bashrc-and-bash-profile