A former All-Pro football player with the Green Bay Packers, Walter Langkowski became involved with Department H's scientific department while working as a professor of biophysics at McGill University in Montreal. While attending Pennsylvania State University, Walter had gotten to know Bruce Banner (The Hulk) who had an influence on Walter, inspiring him to pursue his own studies in Gamma radiation.
When Walter learned how Gamma radiation had turned Banner into the Hulk, Langkowski (already involved with Department H) attempted to replicate the process with himself as the test subject in a more controlled environment. Langkowski's experiments seemed to be successful as he discovered he had transformed into the 10-foot, orange fur form of Sasquatch. He assumed that the colouration difference between himself and the Hulk was due to sunspot activity over his northern research laboratory. In truth, the Gamma radiation was not what had given Walter his powers. The intense release of energy breached the mystical barrier between Earth and the Realm Of The Beasts. During the split-second dimensional breach, the essence of the Great Beast Tanaraq escaped, taking refuge in the body of Walter Langkowski, thereby endowing him with the power of taking the Great Beast's form at will.
When Walt's fellow Alpha Flight member, Snowbird eventually learned the nature of his powers, she was forced to take action. Snowbird had been put on Earth by the Northern Gods to destroy the Great Beasts as they appeared. Snowbird took the form of an albino Sasquatch, and ripped out Langkowski's heart. In death, the spirit of Tanaraq, fled to the Realm Of The Beasts, dragging that of Walter with it. Alpha Flight crossed the dimensional barrier and brought back Langkowski's soul. Having no body within which to place the soul, Shaman transferred it into the robotic Box armour.
Roger Bochs (designer of the Box armour) and Langkowski went looking for a mindless body in the Interdimensional Crossroads. The body they located turned out to be that of the Hulk. While trying to bring the Hulk's body across the dimensional barrier, Langkowski's soul became trapped in the Crossroads. After some time, Walter came across the mindless body of Smart Alec, an enemy of Alpha Flight that Shaman had shrunken and put into his medicine pouch (a door to all dimensions). Taking over the diminutive body, Walter used it to escape the nexus through Shaman's pouch. He emerged to find Snowbird's dead body in the albino Sasquatch form possessed by the evil being Pestilence. Langkowski then moved back into the uninhabited Box armour to battle with Pestilence in the Albino Sasquatch form. He expelled the soul of Pestilence, and took over the newly vacated body of the Albino Sasquatch. When Walter switched back to human form, he was shocked to find out that he was now a woman. Since it had been the body of Snowbird, it retained its female nature despite being the house for a male's soul. Walter then took on the name of Wanda Langkowski.
Some time later during a battle with the Dreamqueen, Wanda had fallen under the evil demon's power and had stolen the Talisman. At that point Snowbird's spirit descended and restored Langkowski's body to that of a man, thereby breaking the control of the Dreamqueen. From that point on, Walter continued to serve with Alpha Flight, now again able to take the orange form of Sasquatch. It is not known if he still bears a connection to Tanaraq.
After Alpha Flight had been disbanded by the Canadian government, Langkowski was doing research at the North Pole, when he came upon the Frozen form of James MacDonald Hudson. With Hudson, Shaman, Northstar, and Aurora they deposed the then corrupt Department H, rejoining Alpha Flight. That version of Alpha Flight unfortunately did not last long.
Most recently, Langkowski has taken steps to form a new Alpha Flight with a host of new members. When he, along with the rest of Alpha Flight investigated a potential Plodex attack, they were all captured except for Sasquatch. Sasquatch led an All New, All Different Alpha Flight strike force he had assembled and freed his companions. The newly freed Alphans decided to transport the Plodex eggs back to the Plodex home world to give them a chance to build a fresh civilization.
Most recently, Sasquatch was involved in the battle against The Collective. He appeared to be badly injured or possibly killed.