The memorial names the Hillhead High pupils who made the ultimate sacrifice and the service was held at the school's Hughenden sports ground in the West End.
Guests laid wreaths at the memorial that lists a total of 183 former pupils who died in the First World War and the 84 who died in the Second World War.
Reverend David Sinclair of Wellington Church, who is also the chaplain at Hillhead High, led the service.
Tom Gardner, a former Hillhead High pupil, played the last post and reveille with Callum MacLellan, a piper from the city's Gaelic School.
The rededication follows a refurbishment of the clubhouse, which was built in 1924 in memory of the First World War dead.
Tony Green, the chairman of the Hillhead High School War Memorial Trust, said: "With the march of time it is easy to forget that the original purpose of our sports club was to function as a memorial to former pupils of Hillhead High School who served and gave their lives during the Great War.
"We also honour those fallen in the second global war of the 20th century."