One of the most well-known historical figures in Karolia, his portrait appears on the reverse of the Kr20 banknote, as well as having Maasriiäs Ot, the central avenue in Säntjana on which the Karolian parliament and ministries are located, named after him. He was voted fifth in a poll of the '50 Greatest Karolians' in 2000.
Maasriiäs was born the second son of a landowning family in modern Hiimamae state. He was educated at Känton university studying law and was noted by his fellow students and teachers as having an aptitude for rhetoric and argument in debates. His time there coincided with the growing Nationalist movement and in particular the publication of the Karolian national epic, the Vaaräsiin, which became the centre of the movement.
After a brief period in the legal profession, Maasriiäs joined the army of Säntjana soon after the outbreak of the War of Unification in 1787 and was trained as a cavalry officer. He saw some active service in the battles between the two alliances, but his main contribution to the conflict was actually as an emissary and diplomat. He was jointly responsible for the decisive action of persuading General Aleksii Säenieme to form an alliance with Säntjana, bringing the substantial army of Paliiso into the conflict.
After the war ended with the peace treaty that created the first republic, Maasriiäs was appointed Elector of Fontjäna, then in 1800 Chief of the Diplomatic Service after the unexpected death of his predecessor. Although happy in the role, Maasriiäs was privately persuaded by the incumbent president to run for the office in the 1803 election.
Maasriiäs was sworn in by the Riikskogu in Fontjäna on August 24th, 1803. He established the tradition of having the city drum and bugle corps play a new fanfare preceding the national anthem: every successive president has commissioned a new piece of music for this element of the ceremony. He was re-elected by national ballot in 1807. During his two terms he oversaw the modernisation of federal laws and land reform, the establishment of the first state schools and the restoration of mining and lumber industries to foreign export.
After retiring from public politics at the end of his second term in 1811, Maasriiäs moved to a modest by comfortable country house in Hiimamae and began to produce several books on politics, history and law.
Maasriiäs was known for his meticulous and tireless attitude, often working longer than was good for his health in later life. He would often become irritated with those who took too long to grasp ideas or whose reasoning was weak, and was known to be particularly disdainful of simple, sentimental ideas and idleness. He distinctive orange hair and fast walking pace gave rise to several nicknames. On the other hand, Maasriiäs would always be willing to support those who he felt would achieve great potential, purchasing the work of several nationalist artists in retirement and aiding the careers of younger politician (never forgetting the encouragement he has received from the President).
Maasriiäs married young to Sanne Torvolainen, daughter of another landowner. The marriage seems to have been happy but unsentimental, with Sanne bearing him four children, all boys. Maasriiäs had an uneasy relationship with his older brother Timo who had inherited the family estate and whom he felt was too idle and reluctant to better himself (this view seems to have been somewhat unfair; the estate was well managed and Timo both fought in the war and successfully invested in several oceanic trade companies once the country was stable).
Maasriiäs' retirement house is now a public museum dedicated to his life and achievements.
A prominent statue was erected in 1870 at the western end of Maasriiäs Ot, outside the parliament building. Other monuments exist in his home town.