In this marriage, three sons were born, whose baptismal names along with other attention and courtesy to the older generations of the family burst testimony to Marcus Wallenberg's classic interests and perhaps also hopes or predictions about the boys' most distinguished characteristics before or during the impending journey through life.

The oldest of the brothers was called Marcus Hilarion (the happy one), the middle one Jacob Agathon (the good) and the youngest André (Andreios – the powerful, the tenacious) Oscar.

He now began to engage in business, became a Burgess of Sundsvall, to be eligible for election to a member of parliament and was discharged from military service in 1851 with the rank of premierlöjtnant.

Wallenberg also took an active part in the formation of the Skandinaviska kreditaktiebolaget, and it was to his credit that this bank's head office wasn't placed to Copenhagen, which Carl Frederik Tietgen wanted, but to Gothenburg.

[3] Among those to whom he devoted special interest may be mentioned: the introduction of the metric system, the adoption of gold standard as a unit of account, the development of banking legislation, the cancellation of the compulsory rate on the Riksdag's banknotes in accordance with §72 of the Constitution, the cancellation of the Riksdag's sovereignty over Sveriges Riksbank, the introduction of the irrevocable 4 per cent bonds as a type for Swedish government loans, reforms in the debt collection and bankruptcy law, abolition of the wool discount and the convoy commissariat (konvojkommissiariatet), new provisions concerning the measurement of ships, port tariffs, pilotage, improvement of officials' pay conditions, introduction of open voting in parliament, determination of unmarried women's age of majority to 21 years, extension of the right of married women to themselves take possession of inherited and acquired property etc.

Wallenberg, who was a member of the Committee of Supply from 1867 to 1870, otherwise made himself known as one of the power-owning Lantmanna Party's most unforgiving adherents and was vigorously active at the Riksdag of 1883 to bring the army order and tax proposals of Arvid Posse's government to a fall.

[4] In 1867 Wallenberg was Sweden's official representative at the international monetary conference in Paris, where his proposal that all states should agree on the same alloy in the gold coins was adopted.

His financial activities are characterized by rare foresight, paired with energy and power, but also by a ruthlessness that made him, before and after his death, one of the more contentious.

[1] Wallenberg married in 1846 to Catharina Wilhelmina ("Mina") Andersson (1826–1855),[5] with whom he had four children; the daughter Oscara (1847–1863), the sons Jacob (1851–1872), Knut Agathon (1853–1938), and Wilhelm (1855–1910).