How old is Hal Jordan really?
TL,DR: Hal Jordan was most likely mid to late 20s when he received the ring and approximately early to mid 40s when he became Parallax.
- I give precedence to mentions of aging + time passing in Green Lantern comics versus his appearance in others.
- This will be pre Zero Hour continuity as he was retroactively deaged during that arc (and the timeline was shortened to 10 years).
- I will be treating pre-crisis and post crisis Green Lantern comics as one continuity because the pre-crisis Green Lanterns survived the crisis
- I will be assuming that at the youngest Hal was 18 when he joined the military because Hal has been shown to be rule abiding in that regard.
How Old Was Hal when he received the ring?
Pre-crisis, he was no younger than 28. Post crisis, he was no younger than 25.
In Green Lantern (1960) #36, it is established that Hal's best friend in the Air Force was a man named Bill who died in the Korean War. As this comic came out in 1965, if he joined during the last year (1953) of the war at age 18 (the youngest possible age), he would be 30 during this comic. While there was not any direct reference to time passing in issue 36, in Green Lantern (1960) #27, at most 3 and a half years had passed since he became a Green Lantern and at least two and half years had passed overall. This makes him no younger than 28 when he became a Green Lantern. This makes sense with other established timelines, such as the fact that Jim (Hal's "kid brother" as he calls him in Green Lantern (1960) #22) is already out of college and has been for a while and that Hal was complaining about kids these days in the 60s. He was written as an older character, with several issues contemplating on how much stuff has changed.
Post crisis, the main timeline changes happened in Green Lantern (1990) and the surrounding Green Lantern books. In Green Lantern: Emerald Dawn II #1, Hal is noted as having flown missions in Vietnam and for this to have happened several years before. In addition to flying in Vietnam, he was a test pilot which requires a college degree plus at least 3 years of military experience. He most likely was at the very least 25 during this point.
Timeline Mystery: When Did GL/GA Happen?
Green Lantern (1960) #76 (the first issue of Green Lantern/Green Arrow) most likely happened eight years after Hal became a Green Lantern.
This timeline assumes 3 years between Showcase #22 and Green Lantern (1960) #27 (the midpoint of the smallest amount of time possible and the largest time possible), takes note of the fact that there is a year between Green Lantern (1960) #42 and #52 (note: #52 is set pre Green Lantern (1960) #49, in which Hal self exiles himself from Coast City). In addition, it assumes 3 years between Green Lantern (1960) #49 and #74, taking into account the several six month/year long time mentions in those issues and the fact that Tom had three children within that time frame.
There being eight years between Hal becoming Green Lantern and gl/ga makes sense, especially since in Green Lantern Corps (1986) #201, it has been five years since GL/GA and in Green Lantern Corps #215, it has been 12 years since the start of the Solar Director arc which started in Green Lantern (1960) #8, which was over a year since Hal became Green Lantern but less than two.
How Old Was Hal when he became Parallax?
Hal was, at the very least, 41 when he became Parallax. He was at the very least 40 during Green Lantern (1990) #1 and there was a year long period between Green Lantern (1990) #1 and #48.
This number bases on the fact that he was at least 25, and there is fifteen years between Green Lantern: Emerald Dawn (1989) and Green Lantern (1990).
Hal being at the very least 40 makes sense because during this era he was supposed to be older. In fact, Adam Strange even teases him about going cosmic in his old age (Green Lantern (1990) #38) and he's called old by Guy (Green Lantern (1990) #25). Hal even complains about how much his back hurts and how it didn't hurt this much when he was 30 (Green Lantern (1990) #32). He's supposed to be older than this era, the one people look up to, the one who is tired of always doing what is right but hurts himself in the end. His age is an important aspect of the narrative. Erasing this weakens what the passage of time and growing up means to him.