In 1807, Berzelius was appointed professor in chemistry and pharmacy at the Karolinska Institute.  Between 1808 and 1836, Berzelius worked together with Anna Sundström, who acted as his assistant and was the first female chemist in Sweden.
In 1808, he was elected a member of the Royal Swedish Academy of Sciences. At this time, the Academy had been stagnating for several years, since the era of romanticism in Sweden had led to less interest in the sciences. In 1818, Berzelius was elected the Academys secretary and held the post until 1848. During Berzelius tenure, he is credited with revitalising the Academy and bringing it into a second golden era (the first being the astronomer Pehr Wilhelm Wargentin's period as secretary from 1749 to 1783). He was elected a Foreign Honorary Member of the American Academy of Arts and Sciences in 1822. In 1827, he became correspondent of the Royal Institute of the Netherlands, and in 1830 associate member.
In 1837, he was elected a member of the Swedish Academy, on chair number 5.