Clothing has been hand-washed for thousands of years, by flushing water through the fabric to remove loose dirt, rubbing with soap to remove oils and stains, and applying fragrances to cover odours. For particularly dirty clothing caked with mud or dirt, it was necessary to constantly rub and flex the cloth to break apart solids and help the soap penetrate through thick, dry, or sticky layers of soil on the cloth. At first this was done by pounding or rubbing the clothing with rocks in a river, and later developed into the corrugated wash board. In Roman times a fuller would whiten clothing by stomping on it in a bucket full of fermented urine.

Washing machine technology was initially developed as a way to reduce the physical drudgery of this labourious scrubbing and rubbing process, by providing an open basin or sealed container with paddles or fingers to automatically agitate the clothing. The earliest machines were often hand-operated but were built with the belief that the machine itself was faster and easier to operate than washing the clothing by hand directly. As electricity was not commonly available until at least 1930, these early machines were often operated by a low-speed single-cylinder hit and miss gasoline engine.

Because water usually had to be heated on a fire for washing, the warm soapy water was precious and would be reused over and over, first to wash the least soiled clothing, then to wash progressively dirtier clothing. The load of soaking wet clothing would be removed, and another load of dirty clothes added to the machine. While the earliest machines were constructed entirely from wood, later machines made of metal permitted a fire to burn below the washtub, to keep the water warm throughout the day's washing.

Removal of soap and water from the clothing after washing was originally a separate process. The soaking wet clothing would be formed into a roll and twisted by hand to extract water. To help reduce this labour, the wringer/mangle was developed, which uses two rollers under spring tension to squeeze water out of the clothing. Each piece of clothing would be fed through the wringer separately. The first wringers were hand-operated, but were eventually included as a powered attachment above the washer tub. The wringer would be swung over the wash tub so that extracted wash water would fall back into the tub to be reused for the next wash load.

The modern process of water removal by spinning did not come into use until electric motors were developed. Spinning requires a constant high-speed power source, and was originally done in a separate device known as an extractor. A load of washed clothing would be transferred from the wash tub to the extractor basket, and the water spun out. These early extractors were often dangerous to use since unevenly distributed loads would cause the machine to shake violently. Many efforts have been made to counteract the shaking of unstable loads, first by mounting the spinning basket on a free-floating shock-absorbing frame to absorb minor imbalances, and a bump switch to detect severe movement and stop the machine so that the load can be manually redistributed. Many modern machines are equipped with a sealed ring of liquid around the top of the basket that works to counteract any imbalances. It is crucial to avoid allowing these types of modern machines to remain in freezing temperatures, as this fluid will freeze, causing seams to split, allowing this damping fluid to slowly leak out. Once this fluid is absent, washing machines so equipped will be highly likely to shake violently and move about the floor.

What is now commonly referred to as an automatic washer was at one time referred to as a washer/extractor, which combines the features of these two separate devices into a single machine, plus also includes the ability to fill and drain water by itself. It is possible to take this a step further, to also merge the automatic washing machine and clothes dryer into a single device, but this is generally uncommon because the drying process tends to use much more energy than using two separate devices; a combined washer/dryer not only must dry the clothing, but also needs to dry out the wash chamber itself.