Major General Hammond was the head of the USAF's Stargate Command. He replaced Major General West who commanded the Stargate Project during the original excursion to Abydos (in the original movie Stargate). An Air Force officer since the mid-1960s, shutting down the Stargate program was to have been his last assignment before retirement.

Master Bra'tac has been known to call him "Hammond of Texas", referring to Hammond's home state (and, because other characters who are members of the American military are seen to do so, he occasionally gives a semblance of a salute by gesturing with a hand over his head). Hammond is a widower; his wife died of cancer. He has two grandchildren, Kayla and Tessa, whose phone number is keyed to the '1' button on his office phone above the president.

He is very dedicated to the men and women under his command as shown when SG-1 was captured by Hathor and he went to any lengths to rescue them, including going into battle himself in a successful attempt to save them. Hammond briefly retired under duress in 2001 and left the series at the beginning of season 8, when he was promoted to the rank of Lieutenant General and placed in command of the new Homeworld Security command, a department which was in control of Stargate Command, the Prometheus project, and the Atlantian Antarctica outpost.

In 1969, Lieutenant Hammond met SG-1 from approximately 30 years in the future and read a note that he had written to himself. After SG-1 broke out of military custody, Jack O'Neill shot Hammond with a zat gun in order to protect Hammond from a court martial for helping the team escape.

Before his promotion, President Henry Hayes, former air force colleague of Hammond's, put the general in charge of Prometheus during the battle in Antarctica against the forces of Anubis. Hammond later made guest appearances during the first season of Stargate Atlantis and the eighth and ninth seasons of Stargate SG-1. An alien on a planet in the Pegasus galaxy impersonated Hammond while making contact with the team assigned to Atlantis. The real Hammond commanded a short-lived and fruitless mission to take Prometheus to Atlantis. However, that mission did bring the SGC into contact with Vala Mal Doran.

General Hammond apparently retired from active service sometime in season 9; in The Fourth Horseman (Part 1), he was wearing a civilian suit. His retired status was confirmed in the 10th season episode The Road Not Taken by Carter. He returned to the show in a voice cameo for the tenth season episode 200 and as an alternate version of himself in The Road Not Taken. Although he retired he did seem to have some kind of important civilan posistion in the government as he gave a speech to gathered people at an Air Force base and was hustled away by the Secret Service when there was a threat in the area.

His most recent appearance was in Stargate Continuum. He was a Lieutenant General and seemed to hold a high posistion as he acted as a military advisior of sorts to President Hayes during the Ba'al situation. This General Hammond did not know Colonel Carter's alternate self as was proven when she said it was nice to see him and he responded "if you say so" while seeming confused.

Source | Wikipedia.org