In the fall of 1974, after attending Berklee College of Music, Walter Thompson moved to his family’s summer home in Woodstock, New York. He received a grant from the National Endowment for the Arts to study composition and woodwinds with Anthony Braxton and also studied dance with Ruth Ingalls. Woodstock in the 1970s was a hub for creative music, largely due to the Creative Music School (CMS) founded by Karl Berger. CMS attracted notable composers and performers such as John Cage, Ed Blackwell, Carlos Santana, Don Cherry, Anthony Braxton, and Carla Bley, who conducted master classes culminating in performances.

During his first summer in Woodstock, Thompson organized jam sessions and formed his first orchestra, which included 22 musicians and 7 dancers who improvised to the music. He produced a series of concerts at Woodstock’s Kleinert/James Gallery, focusing on compositions with open-form improvisation. It was during this time that Thompson created his first signs, which would later become the Soundpainting language. The initial gestures, such as Long Tone and Pointillism, were developed to guide improvisations during performances.

In 1980, Thompson moved to New York City and formed The Walter Thompson Orchestra. During a concert, he attempted to use his signs to communicate with the orchestra, but they were unfamiliar with them. This led to teaching the orchestra the signs, which they responded to positively. Over the next decade, Thompson developed Soundpainting into a comprehensive sign language with over 200 gestures for real-time composition with musicians.

In the mid-1990s, Todd Reynolds, a member of Thompson's orchestra, urged Thompson to teach him Soundpainting. This marked the beginning of Thompson sharing the language globally.

In 1990, Thompson expanded Soundpainting to include actors for a commissioned work at Lincoln Center. He incorporated actors Leese Walker and Josh Taylor, who responded to gestures with voice and movement, engaging the audience in interactive performances. This success led to actors becoming a permanent part of his orchestra.

Thompson's work with dancers began a few years later when choreographer Margery Segal commissioned a piece for 100 dancers and 35 musicians. Thompson and Segal spent weeks codifying gestures for dancers, resulting in a successful outdoor performance in Austin, Texas. This experience led Thompson to further develop Soundpainting with choreographer Gus Solomon, integrating musicians, actors, and dancers into a multidisciplinary group.

In the late 1990s, Thompson introduced Soundpainting in Europe through a workshop at the International Association of Schools of Jazz (IASJ) Conference in Santiago de Compostela. This led to further invitations to teach and perform, notably at the Conservatoire de Paris. François Jeanneau, inspired by Thompson's workshop, became a prominent advocate of Soundpainting in Europe.

Today, Soundpainting is a living language with over 1300 gestures, used in professional and educational settings worldwide. To maintain the language's coherence and foster its development, annual Soundpainting Think Tanks have been held since 1997, bringing together experienced Soundpainters to share ideas and expand the language. Although the pandemic caused a pause in 2020 and 2021, the tradition of Think Tanks has continued otherwise, ensuring the ongoing growth and evolution of the Soundpainting language.