Following the 1798 French invasion, Sumiswald became the capital of the Helvetic Republic district of Unteremmental. After the collapse of the Republic and 1803 Act of Mediation it joined the newly created Trachselwald District. In the 19th century the local yarn and cloth industry declined and was replaced with other industries including manufacturing musical instruments. The construction of the Emmental road in 1875, the Ramsei-Huttwil railroad in 1908 and the Sumiswald-Wasen rail line in 1915 brought new factories and industry to the municipality. Today Sumiswald is a regional cultural and economic center, with workers commuting into the municipality from surrounding villages. There are secondary schools in Sumiswald and Wasen as well as a retirement home.