He was a junior executive with the Weyland-Yutani Corporation. He acted as a representative of Ellen Ripley, while she was being investigated because of her actions at the Nostromo after her rescue from deep space in 2179 and later accompanied a squad of Colonial Marines on board the Sulaco to LV-426, the moon, where Ripley had first encountered the Xenomorph species, to investigate the loss of contact with the established colony there.
While initially amicable towards the Marines and Ripley in particular, in reality, Burke had ulterior motives and his loyalties lay solely with Weyland-Yutani. He accompanied the mission to get some of the Xenomorphs for the company and it was also him, who sent the colonists to the derelict ship for that purpose without warning them. Noone among the Marines played along with his intentions. Still he continued scheming against the personnel from the Sulaco mission for the purpose of bringing a few specimen to the company to the extent of even trying to impregnate Ripley and Newt and then kill the marines later. He was eventually stopped in the nick of time and he was nearly executed by the surviving Marines for his treachery.
Ultimately, he was killed by the Xenomorphs, when they attacked at that moment. In an attempt not to pay for his actions, he betrayed them again and tried to reach Bishop, but a Xenomorph was waiting for him and killed him.
"I work for the company. But don't let that fool you, I'm really an OK guy!" - BurkeBurke is a a sociopath, a consumate liar and an emotional manipulator that lacks any conscience and human feelings. He only thinks about profit to the extension of even committing mass murder for that, which is probably the reason why the company selected him for this mission in the first place.