He is a yellow fat cat with a bushy tail and red hair.
Winston is a friendly, yet dim-witted cat who is nice to mice like Jerry and Tuffy, thus he does not have any interest in eating or chasing mice. He also doesn't like to be lonely. He is also friends with Tom or Butch sometimes.
Mouse Party is the only episode that Winston chases mice.
Winston's greatest weakness is gluttony, which is reflected by his body shape. He's especially fond of sweets and pastry, which was seen in Stolen Heart, when he hired Tuffy to steal a cake baked not for him.