The planet was discovered orbiting the primary star of the Gliese 777 system in June 2002 (by the Geneva Extrasolar Planet Search Team) using the radial velocity method.

[2] In 2021, the inclination of Gliese 777 Ab was measured via astrometry, allowing the true mass of 1.8 MJ to be determined.

At periastron the distance between the planet and the star is only 2.57 AU and at apastron the distance is as much as 5.23 AU (compared to the Solar System, distance from the Sun to the inner asteroid belt and from Sun to just beyond the orbit of Jupiter).

The signal produced by the planet is very weak and the eccentricity was originally supposed to be very circular which led to speculations of a very Jupiter-like planet, with a system of several large moons like Jupiter itself.

The inner system should be stable for Earth-like planets despite a known, smaller inner Neptune-like planet which is known to orbit the star at distance of 0.12 AU every 17 Earth days.