Hey guys, I recently found fleas on my cat and have been spraying him with a flea killer I got at pet supermarket. It kills a couple of them but they keep coming back. I am planning to fumigate my backyard and porch to kill or prevent any fleas from coming in the porch where my cat likes to go out and relax. What is the best method to fully get rid of these pests? Will I have to bathe him and use flea shampoo? if so, whats the best brand. Any help is greatly appreciated, thank you.

Update: I just bathed him with flea shampoo and used a flea comb to pick all fleas. He clawed the living hell out of my back when he climbed on me to make an escape.