Early procedures for hair transplant  used  scalp flaps, in which a band of tissue with its original blood supply is shifted to the bald area, and free grafts , dating back to the 19th century. Modern transplant techniques started in Japan in the 1930s, where small grafts were used to replace damaged areas of eyebrows or lashes. They did not attempt to treat baldness. These  efforts did not receive much attention at the time, and the trauma of World War II kept their advances isolated for another two decades.

The modern era of hair transplantation started  in the late 1950s, when New York dermatologist Norman Orentreich began to experiment with free donor grafts to balding areas in patients with alopecia. Previously it was thought that transplanted hair would thrive no more than the original hair at the "recipient" site. But Dr. Norman showed that such grafts inherited donor characteristics  as the new hairs grew and lasted just as they would have at their original site.

Advancing the theory of donor dominance, Dr. Walter P  defined  the "Safe Donor Zone" from which  permanent hair follicles could be extracted for hair transplantation. As these follicles will  grow in the new site for as long as they  would have in the original site, these parameters continue to serve as the fundamental foundation for hair follicle harvesting, whether by strip method or FUE.

For the next twenty years, surgeons worked on transplanting smaller grafts, but results were only minimally successful, with 2–4 mm "plugs" leading to a doll's head-like appearance. In the 1980s, Dr. Uebel from Brazil popularized using large numbers of small grafts. In USA Dr. Rassman started using thousands of “micrografts” in a single session.

In the late 1980s, Dr. Limmer introduced the stereo-microscope to dissect a single donor strip into small micrografts.

The hair transplant procedure has continued to evolve, becoming more refined and minimally invasive as the size of the graft incisions have become smaller. These smaller and minimally invasive incisions allow surgeons to place a large number of grafts into a given area. With the new "gold standard" of ultra refined follicular unit hair transplantation, over 50 grafts can be placed per square centimeter, when appropriate for the patient.

Surgeons are also devoting more attention to the angle and orientation of the transplanted grafts. The adoption of the “lateral slit” technique in the early 2000s, enabled hair transplant surgeons to orient 2 to 4 hair follicular unit grafts so that they splay out across the scalp's surface. This enabled the transplanted hair to lie better on the scalp thus providing much better coverage. One disadvantage however, is that lateral incisions also tend to disrupt the scalp's vascularity more than sagitals incisions.Good  hair transplant surgeons typically adopt a combination of both methods based on what is best for the individual patient.

With the latest improvements in surgical technique and especially with the FUE procedure, the recovery time is immediate and the pain negligible. There is no bed rest or hospitalization required after the hair transplant.