Founded in 1910, it has sections for association football, bandy, baseball, cycling, gymnastics, handball, judo and skiing.

The club is best known for its football section, Mjøndalen IF Fotball, who has won the Norwegian Cup three times, 1933, 1934 and 1937 and finished in second place in Norway's top tier twice.

After being promoted to the top division in 1971, Mjøndalen regularly played on the top-tier of Norwegian football in the 1970s and 1980s, and finished second in 1976 and 1986.

However, Mjøndalen's silver medals saw the team qualify for the 1977–78 UEFA Cup, where they lost the first round against Bayern Munich 0–12 on aggregate.

A highlight from the years in lower divisions was their meeting with German side Werder Bremen in the first round of the 1987–88 UEFA Cup.