The White House on Friday released a 2.5-inch-thick stack of documents in its latest effort to quash charges from Democrats that he shirked his duties from May 1972 to May 1973.
Bush avoided possible combat in Vietnam by joining the Texas Air National Guard and training as a fighter pilot.
The records released on Friday show Bush joined the Texas Air National Guard in 1968 and received high marks as a fighter pilot until he was suspended for flying in August 1972 after failing to take a required annual physical examination.
The suspension came after Bush had moved to Alabama to manage a Senate campaign.
According to the records, Bush had requested a transfer to a reserve unit in Alabama.
That request was denied because he had not yet fulfilled his six-year Guard commitment, and Bush's superiors instead allowed him to perform temporary duty with a Guard unit in Alabama.
No proof of service
The president's opponents have questioned whether he performed his duty during that period, noting that there is no proof of his service.
The records released on Friday are unclear on that point. They show his service from May 1972 to May 1973 was sufficient to earn retirement credit for that year, but do not indicate where or how it was performed.
Bush was released from the Guard eight months early in October 1973, after the US had withdrawn its troops from Vietnam as part of a peace deal.
He was transferred to the inactive reserve and was discharged in November 1974.