To become a therapy dog trainer, you will need to have experience working with animals and knowledge of training methods. One way to start on this career path is by working as an assistant or apprentice for a professional trainer. Another option is to enroll in a training program and gain 2-4 years of experience. Taking classes in animal behavior and animal science can also be beneficial. Additionally, some charitable organizations offer volunteer opportunities for those interested in training service animals. Keep in mind that some states may require you to pass a licensing exam.