Walter Langkowski replaced his religious faith early on with a belief in and a dependence on science. He attended Pennsylvania State University on a football scholarship, where he met Robert Bruce Banner and became interested in gamma ray research. After graduating, Walter pursued his research independently while accepting a position with a professional football team, the Green Bay Packers, and married Veronica, an actress who bore him a son. After earning over a million dollars, Walter retired and returned to school, soon earning his Ph.D. from the Massachusetts Institute of Technology. Walter began teaching at McGill University in Montreal and furthered his gamma ray research, including studying Banner’s famous transformation into the Hulk, and Veronica soon divorced him, taking their son. At a new position with the Canadian government’s Department H, Walter worked with James Hudson, whose plans for a new super-hero team would eventually lead to Alpha Flight. Langkowski acted as technical and scientific support for Alpha’s precursor, the Flight, which included Smart Alec, a brilliant man with access to vast amounts of information, Snowbird, a goddess with the power to change to any Arctic animal, and Wolverine, a vicious mutant with a mysterious past. Eventually, Langkowski exposed himself to gamma rays, hoping to gain powers like Banner’s. Instead he opened a mystic barrier that allowed the Great Beast Tanaraq to pass through, and Walter assumed its form, wrongly believing his powers came from the gamma radiation. At first, Langkowski’s brain and personality remained in control of his monstrous Sasquatch form, and he joined Alpha Flight himself.

Alpha Flight’s roster would change frequently over the years as they went through phases of government contracts and independent action. Walter studied many incoming operatives, who were generally assigned to training teams Beta and Gamma Flight, for Department H. One operative, later known as Wild Child, had a very unstable genotype and psychosis, but the government shoe-horned him into the program anyway. Langkowski buried Wild Child’s unstable results, figuring he would handle them at another time, though he never put much thought into it. In Alpha Flight’s earliest missions, Sasquatch battled the X-Men, the Hulk, Sunset Bain, Machine Man, Tundra of the Great Beasts, Ranark the Ravager and Wendigo. Sasquatch also participated in the "Contest of Champions" organized by the Grandmaster and Death, and, as one of the Grandmaster’s operatives, battled the Chinese Collective Man to a stalemate. Langkowski was consulted by the Fantastic Four for his radiation expertise, and battled the Dire Wraiths, Omega Flight (in a battle where Hudson was believed killed) and the Collector.

Becoming fast friends with the diminutive Puck, Walter started a romantic relationship with the light-powered Aurora, a fact her twin Northstar resented immensely. Walter and Aurora’s relationship became complicated when Aurora began struggling with split personalities, one that liked Walter and one that didn’t. In the process of trying to help Aurora retain her more outgoing personality, Walter altered her mutant powers. Sasquatch discovered his ability to quickly heal from injuries after he broke his arm in a battle with the Super-Skrull.Langkowski eventually began struggling with a more bestial side of his nature during various battles, and feared he was becoming more like the Hulk. When his aunt, Lillian Von Loont, left Walter a mansion on Tamarind Island, Walter and Aurora investigated only to battle Loont, who had become the cyborg madwoman Gilded Lily. This mansion would later serve as Alpha Flight’s headquarters for a time. Sasquatch, alongside Alpha Flight and the X-Men, was temporarily cured of his rages by a Loki-possessed Madelyne Pryor.

Snowbird, whose mission it was to slay the ancient Great Beasts who had roamed the Earth before mankind, discovered that Walter’s Sasquatch form was actually Tanaraq, and Walter was now losing control. Left with no choice, Snowbird followed Alpha Flight’s battle with Caliber and slew Sasquatch by ripping out Tanaraq’s heart. Alpha Flight pursued Walter’s soul into the realm of the Great Beasts and battled their leader, Somon who killed Aurora, Northstar and Talisman before Langkowski used his life-force to resurrect them. Shaman helped preserve Walter’s soul as they transported back to Earth, only to discover that Walter’s body had been destroyed completely. Walter’s soul took over the Roger Bochs created Box armor as a temporary home and continued aiding Alpha Flight. Seeking a physical body, Walter entered the interdimensional Crossroads and briefly possessed the Hulk, but his soul was left adrift when he refused to displace his old friend Bruce Banner’s spirit. Months later, Walter found Omega Flight’s now-mindless Smart Alec in the Crossroads, possessed him, and returned to Earth.

During his absence, Snowbird had been killed, and the evil Pestilence had reanimated her albino Sasquatch form and attacked Alpha. Walter inhabited the Box armor again and aided his team, who were shocked to find him alive. At the battle’s end, Smart Alec’s form had been crushed and the Sasquatch form left empty, so Walter transferred his soul to the Sasquatch form; however, when he returned the Sasquatch body to human state, he found himself in a woman’s form. Deciding to call himself Wanda, Langkowski rejoined the team, possessing none of Snowbird’s powers except the ability to transform into the Sasquatch. Aurora was distressed at Langkowski’s return as a woman and attempted to get the flesh-altering Lionel Jeffries to alter Wanda’s form to a man again, but this failed due to Wanda’s body having Snowbird’s godly attributes. Wanda struggled to adjust to her new form, and, after batting Bedlam, was overcome by a mysterious force and helped resurrect four of the Great Beasts. Overcoming the temptation to join them, Sasquatch helped Alpha Flight banish the Beasts back to their realm. After brief jaunts through space and Dream Queen’s dimension, Wanda sought to reclaim Langkowski’s fortune to help fund Alpha Flight, but the fortune had been willed to Veronica; unable to prove she was Walter, Wanda left the fortune in Veronica’s hands. In final battle with the Dream Queen, Sasquatch was bewitched to be loyal to the villain until Snowbird’s spirit freed Sasquatch from the spell and changed Wanda’s form back into Walter’s; this also changed the albino Sasquatch form back into the orange one, and enabled Walter to reclaim his fortune.

The team battled Llan the Sorcerer, a villain who briefly broke both of Sasquatch’s arms (though the injury soon healed). When Alpha Flight restructured itself, Sasquatch was assigned to both Alpha Flight and Gamma Flight, in the latter as Biotech research and development. When Wild Child joined the team as Weapon Omega, Walter struggled with guilt over his part in Wild Child’s origins and the truth soon came out, causing several team members to distrust Sasquatch. Alpha Flight continued to act as super-heroes despite breaking ties with the Canadian government over the newly instituted Super Powers Act. Struggling with all he had lost over the years by devoting all his time to Alpha Flight, Sasquatch was easily drawn into following the mystical Goddess, the "good" side of Adam Warlock’s soul, who controlled Sasquatch and others into battling fellow heroes for her cause. Remembering his doubts regarding religion, Sasquatch shook off the Goddess’s influence with Shaman’s help, and the Goddess was soon defeated.

Though Alpha Flight soon disbanded, Walter continued his gamma ray research at Project Michelangelo in Antarctica. Months later, the mercenary Deadpool attacked the base and caused the core to overload, endangering the entire world, so Sasquatch and Deadpool teamed up to shut it down. The Canadian government, in forming a new Alpha Flight, discovered a true bestial Sasquatch in the woods and assumed it was Walter. Finding ways to subdue the beast, they had this Sasquatch participate in team missions until it was killed while battling Ecliptic’s Zodiac, and the team held a funeral for Walter. Still in Antarctica and unaware of the new team, Walter discovered corruption in the Canadian government. Sasquatch helped gather some of the original team and the group exposed the corrupt government program, then stayed on to rejoin Alpha Flight. While aiding Wolverine (actually a Skrull imposter)in a battle against A.I.M. (Advanced Idea Mechanics), Alpha Flight was shocked to find Snowbird alive again. Walter and Aurora became romantically involved once more, but Aurora was soon terrorized by Mauvais and kidnapped by the corrupt Weapon X program, leaving no trace of her whereabouts. When Alpha Flight went up against the X-Men again, Sasquatch briefly donned battle armor that allowed him to defeat a weakened Juggernaut.

When all of his teammates were captured by the alien Plodex, Sasquatch recruited new heroes, formed a new Alpha Flight and rescued his former teammates. The former Alpha Flight members left for space, leaving Sasquatch’s team to take their place, move into the Plodex base, and sever ties with the Canadian government once again. Alpha Flight embarked on a complicated time travel adventure before the original Alpha Flight members returned and rejoined the team. After speaking at Northstar’s funeral and battling Sabretooth and Wendigo, Sasquatch briefly participated in S.H.I.E.L.D.’s Howling Commandos team. He later accompanied Alpha Flight in investigating the powerful mutant Collective, but they swiftly fell before his assault. His teammates Guardian, Major Mapleleaf, both Pucks, Vindicator, and Shaman, were all apparently killed and Alpha Flight was disbanded in the wake of the tragedy. However, a new team was quickly assembled by CSIS to replace them, this time called Omega Flight. Sasquatch was selected to serve as team leader of the new group, charged with the mission to defend Canada's border against criminals fleeing from the American Superhuman Registration Act. When the American super-villain team the Wrecking Crew invaded Canada, Sasquatch confronted them solo, only to suffer a severe beating at their hands.