He also founded the Liberal Party of Finland (1880–1885), wrote its program, was one of the founders of the Union Bank of Finland 1862 (now part of Nordea Bank) and co-founded the Nokia Company (1871) with Fredrik Idestam, was the first chairman of the town council of Helsinki (1875–1876 and 1892–1899) and an internationally respected expert on politology and member of peace movement.
Mechelin led the passive resistance in Finland during the first period of oppression (1899–1905) until and even after his banishment (1903), from which officials had to let him return as a member of parliament (House of Nobles) 1904, welcomed by a celebrating crowd of 10,000 people.
In a secret meeting of the Kagaali, Mechelin had written a petition against the draft of Finns to the Russian army, which collected almost 500,000 signatures.
Nokia, once a world-leading mobile phone corporation, was founded by Mechelin and his student days' roommate Fredrik Idestam as a forestry company.
[3] Leo Mechelin has received several accolades and honorary dedications following the Russian revolutions and the Finnish Declaration of Independence, including several streets named after him such as Mechelininkatu (in Helsinki) and Mechelinintie (in Hamina).