Though the primary function of the Havanese breed has always been to provide companionship to its human owners, the breed's characteristics have allowed it to be employed in a wide variety of settings. Especially thanks to its cheerful, happy-go-lucky personality and the ease with which it can be trained, this dog does well in jobs that have to do with the public and helping other people; in other words, it makes an excellent pet therapy and assistance dog, helping individuals with physical and emotional disabilities. Havanese have been particularly exceptional as signal, or hearing, dogs.

Hearing dogs are literally the ears of people who are deaf or hearing impaired. There are a variety of organizations that carefully select and specifically train dogs to work with hearing impaired individuals; these dogs are very well trained at signalling to their charges when they hear some important sound, like a doorbell, a telephone, a smoke alarm, an alarm clock, or perhaps the sound of an intruder. Not only do these dogs work with their handlers within the home, but many dogs are also taught how to respond to sounds outside the home; they will signal their owners when they hear things such as someone calling the owner's name, sirens, someone coming up from behind, or heavy machinery. When they hear an important noise, the dog is taught to nudge or put their paws on the handler; for some noises, such as the telephone ringing, the dog then takes the handler to the source of the noise, while for others, such as a fire alarm, the dog leads the handler away from the source of the sound.

Most organizations use dogs that are found in shelters, because besides wanting to help the hearing impaired, they are also intent on rescuing dogs; some organizations also accept donations of dogs. Havanese excel at signal dog work because they react well to sounds, have a very good worth ethic, love to please their humans, and are extremely affectionate and loyal; all individual dogs must pass a temperament test before they begin their training. Dogs are first taught obedience and then they are socialized to a wide variety of people and situations; they are then begun on sound alerting training. Some dogs are trained in about three months, but most dogs take about a year to complete training. Dogs are trained to both distinguish among a large number of sounds and to react appropriately to different sounds when physically signalling their handler; in other words, not only does the dog have to distinguish between a phone ringing and a fire alarm going off, he also needs to understand that his handler must be led TO the phone, but AWAY from the fire alarm.

Hearing dogs, like most assistance dogs, have access to all public structures. To distinguish them from pet dogs, they often wear a bright orange leash and/or collar. There are many organizations that equip the hearing dogs they train with capes or jackets of a specific color to distinguish them. While the majority of hearing dogs are trained by professional organizations, many hearing impaired individuals are beginning to train their own dogs.