The fur of the emperor tamarin is predominantly grey colored, with yellowish speckles on its chest. The hands and feet are black and the tail is brown. Outstanding is its long, white mustache, which extends to both sides beyond the shoulders. The animal reaches a length of 24–26 centimetres (9–10 in), plus a 35 cm (14 in) long tail. It weighs approximately 300–400 grams (11–14 oz).
This primate inhabits tropical rain forests, living deep in the forest and also in open tree-covered areas. This diurnal species walks or runs quadrupedally through the forest, spending the majority of its days in the trees with quick, safe movements and broad jumps among the limbs.
The emperor tamarin lives together in groups of two to eight animals. The oldest female leads the group above several mature males. Mutual grooming plays an important role for bonding and socializing. The emperor tamarin is known to form mixed-species associations with the brown-mantled tamarin (Saguinus fuscicollis). It has various cries which help them to promptly recognize interlopers.