To activate Hulu on your Chromecast device, first ensure both your Chromecast and streaming device are connected to the same Wi-Fi network. Open the Hulu app on your mobile device or computer. Select the content you want to watch and choose the Chromecast icon to cast it to your TV. You will be prompted to enter an activation code. Go to hulu.com/activate on your browser, log in to your Hulu account, and enter the code displayed on your TV screen. Once entered, your Chromecast will connect to your Hulu account, allowing you to stream content directly to your TV.