Jake is a member of the Animorphs and is the unofficial leader of the team. He is the calm voice among others that range from sarcastic and skeptical to emotional and over-reactive. He is the perfect leader. Jake lets everyone else speak their mind while he takes it all in. After everyone has had their say, he summarizes what is actually known versus what is mere speculation. He has a way to leave himself out of the mix and present the facts, risks and consequences of a mission that they are considering. Jake is the team member who provides solid evidence that an alien spaceship has probably crashed in the sea and that a good alien, known as an Andalite, is sending out a distress signal.
Cassie, who is the protagonist and narrator of the story, tells the reader that she thinks Jake is cute and "likes him" likes him. Cassie doesn't let her crush on Jake get in the way of their relationship as team members. Although Jake is usually all business, the fact that he keeps a little picture of Cassie by his computer might be a sign that he returns the feelings she has for him.
Jake impressed the alien Ax who had been sending distress messages from under the sea. In fact, he was so taken with Jake that he dubbed him Prince Jake. But Jake is a humble young man and he asked that Ax just call him Jake.