General Sharp was a military officer in Britain in the 1970s.
When he read reports of the Primords that had attacked the Inferno Project, he became intrigued at the possibilities they presented for military research. Lady Madeleine Rose was won over by his ideas due to her own political ambitions, and agreed to help him conduct his research.
As part of his plans, Sharp recruited Michael, a scientist at Cambridge, and his later fiancée, former UNIT member Liz Shaw, to study the ooze that caused the mutation, officially claiming that they were looking to find a means of protecting people against infection if other samples of the ooze were discovered closer to Earth's surface. After Michael was infected, Sharp told Liz of his true plans to militarise the ooze, apparently winning Liz to his point of view that the ooze would be a useful means of defence, but he was unaware that Liz had been infected by the ooze herself, the mutation corrupting her mind even as Liz's research allowed her to create a serum that stabilised her body before she could change physically.
To provide Liz with further research samples, Sharp and Lady Rose staged various attacks on prison transports, abducting prisoners so that they could test the gas on them. Liz's research allowed her to modify the Primord virus to make those infected invulnerable to bullets, although they would still suffer from exposure to cold.
However, the prison transport attacks attracted the attention of UNIT and other branches of the military, but the Third Doctor and Jo Grant were invited to visit Liz at Cambridge at the same time. Liz was able to infect the Doctor with the Primord virus, while Jo saw a news report on the transport abductions and went to tell the Brigadier about the Doctor's theory that the abductions were being carried out by the military. The Brigadier and Jo were able to determine that Sharp was the most likely candidate as he ran the only military base that hadn't contributed their efforts to the search for the missing prisoners, but by the time the two reached Sharp's base, he had already apparently won the Doctor and Liz over to his point of view.
Although Liz was now freely working with Sharp, the Doctor was able to fight back his infection long enough to give the Brigadier and Jo the necessary clues to escape their cell. Liz was able to release the Primords, forcing Sharp to escape his own base, even throwing Madeleine Rose out of the jeep to distract the pursuing Primords. He attempted to take command of UNIT forces to bomb the attacking Primords, claiming that the Doctor and Liz were traitors while exploiting the fact that the Brigadier had no actual evidence he'd done anything, but the Brigadier rejected that order long enough for the Doctor to join them at the school where they had established their base of operations.
Sharp was kept confined while the Doctor and Jo used the school's chemistry lab to complete Liz's cure, but managed to escape when he distracted his guard. The Doctor was able to cure most of the Primords when Jo added his cure to the school's sprinkler system, but when the outraged Sharp attacked the Doctor, the Brigadier, Liz and Jo, accusing them all of being traitors, he was attacked by Michael, who remained in his Primord state as he had been kept back by Liz because he was an early Primord who was still vulnerable to bullets. Michael and Sharp killed each other before the Doctor could cure Michael. (AUDIO: Primord)