How old is Master Chief?

[Uncle Jon]

I know that at the beginning of CE he was in his forties, but he was cryogenically frozen so I'm thinking in some sort of fashion he should be younger than that physically. At what age was he first put into cryo sleep and how long was he asleep for?

[tuckerthebana]

by halo 5 he was 46 and the only really significant time spent in cryo sleep was between 3 and 4 which lasted about 4 years. Theres also the fact that he was in cryo for months while traveling between systems during the early parts of the covenant war. I dont think that time will ever be truly revealed

[DonkeyBallZ]

Master chief is 41 when Halo CE starts and the events of Halo 2 and 3 take place within about 6 months of that.

After Halo 3 he spends basically all the time till Halo 4 in cryo; so he ages very minimally and is about 42 when Halo 4 starts. He would age about 2 years to 44 by the events of Halo 5 where everyone treats him like he must be some senial senior citizen.

We can also safely say he didn't spend very much time in cyro before the events of CE based on his service record in the human-covenant war.

Timeline:

Chief born March, 2511

Chief has his first combat missions as a Spartan age 14, September 2525

Halo CE starts September 2552, almost 27 years after his first combat deployment

Human-Covenant War Ends December 2552

(Cortana specifically gives the time he is in cyro between 3 & 4 as 4 years, 7 months)

Events of Halo 4 in July 2557

Events of Halo 5 in October 2558

Summary of Service Record:

"By August of 2558, John had completed two hundred and nine military operations, including one hundred and thirty-six full campaigns; more than anyone other UNSC personnel on record at the time.[3] Though John has commanded nearly every Spartan-II at one time or another, the lion's share of his career has been spent as fireteam leader of Blue Team. His actions during the Covenant War earned him every major UNSC service medal and combat award, save for the Prisoner of War Medallion, as well as several dozen civilian honors."

[1999 Ford Mustang GT]

I dont know how old the chief is but he'll be around for a while. I mean sgt. Johnson was In his 70 during the events of 1-3 so I think we'll have the chief in action for years to come.