The 28-year-old joins the Seagulls on the back of a campaign that saw him score eight goals in 35 games for Spanish side Almeria.
Hemed, who has also found the net 10 times in 15 senior international appearances, says that he is 'honoured' to have made a switch to English football.
"Everyone knows about London and how nice it is to visit, so it will be nice to go and see other places in England but first of all I am here to play football, and for me that is most important," he told Brighton's official website
"England for me is the best place to play football. It was a dream for me to come here and play in English football. It is a big honour for me to be here and to start my new challenge in English football here. I can say that this club is the best place for me to start my new chapter.
"I had a great time in Spain with some great moments. I really enjoyed the four years and it was a good experience, but now I am really excited to start my new challenge in English football."