He is best known as the founder of Finland's first veneer factory and for his significant contributions to the chicory, sugar, sawmill, and tobacco industries.

In 1882, he married Wilhelmina "Mimmi" Roos from Jakobstad, and shortly afterward, the couple moved to St. Petersburg, where Wilhelm found work at a mechanical workshop.

Four years later, Mimmi wanted to return home, and the couple moved back to Jakobstad after Wilhelm was denied a position as technical director at Serlachius Mänttä Mill, despite earlier promises.

After completing his engineering studies and working in St. Petersburg, he returned to Jakobstad in 1883 and founded a successful chicory factory, becoming Finland's largest producer in the field.

In the mid-1890s, Schauman diversified his business to other areas, including timber exports, tugboat operations, and sawmill production.

Schauman continued to expand his business empire, and in 1910, he bought a steam-driven sawmill in Yxpila (near Kokkola) and founded a veneer factory in Jyväskylä.

Initially, the raw material was imported from Germany, but Belgium later became the main supplier, followed by the Netherlands, Russia, Estonia, and Poland.

The company flourished as Schauman combined a high-quality product with competitive prices and successful marketing strategies.

He employed his own agents in cities such as Helsinki, Turku, Tampere, and Vyborg, and placed great emphasis on designing attractive packaging with Russian elements like medallions and other decorations.

Chicory production continued after Wilhelm Schauman's death and remained profitable annually between 1912 and 1935, although its contribution to the group's results was relatively modest.

Thanks to successes in the tobacco industry, Strengberg opened new operations in Sweden, Norway, Denmark, and northern Germany.

In 1911, Finland's first veneer factory was founded in Jyväskylä, and Schauman obtained permits for cutting large birches in state forests around Päijänne.

Veneer production quickly developed and remained the most vital part of the company for a long time.

During World War II, the proportion of veneer products significantly increased, and in 1958, a particle board factory was opened in Jyväskylä.

Chicory production in Jakobstad continued after Schauman's death and remained profitable annually between 1912 and 1935, although its overall contribution to the company's results was relatively modest.

At various times in its history, Schauman also acquired businesses unrelated to its core activities, such as furniture manufacturing and other conventional wood products.