Walter Mark "Prof" Haley is a master skin/scuba diver and either a "master scientist" (others' words) or a "dabbler" (his words).

Prof's first name is Walter (COTU V2, New Frontier 3). It's inscribed on his premature gravestone (Adventures of Superman 508). Don't worry, he got better. Plus there was no body, so this is just a monument. Why it's in Metropolis is a question, but maybe it's a memorial park for fallen heroes. Yet one adventure (COTU 83) gives his name as Mark. Perhaps he used that name in college or the Navy, since Walter sounds old-fashioned. Or it may be his middle name: Walter Mark Haley.

"Prof" must also have a PhD, likely in Oceanography but perhaps in Physics or other field. The Challs are notoriously informal, so it's simply Prof, not Doctor Haley. Note he had the nickname before joining the Challs. He introduces himself with it in Adventure 493. Prof has written at least one book. Rocky's read it!

Prof speaks German. Many scientists do. (He's got terrific hearing too, to hear through water, air, and a steel hull.) He speaks other languages too, since Rocky dubs him a "lingo expert" in COTU34. "Beachhead: USA" was a breakthrough in comics, by the way. The revived Germans speak ONLY German throughout, with no translation. Readers have to get their intentions from visual clues and Prof's translation.

	Prof's origin as a Challenger begins in the Mediterranean. Prof Haley was a perpetual student living on money inherited from his Uncle Cyrus - and spending it foolishly while chumming with jerks. The prank of buzzing the sailboat backfired. The owner turned out to be Prof's hero, Sir Lawrence Revere, the marine expert.
Prof makes good by lending Sir Lawrence his diving equipment (top of the line) and helping to rescue a statue sacred to the local fishermen. The statue is saved. But Sir Lawrence is hurt in the process, anchoring it with sheer might and passing out. Prof rescues him, yet wonders what drove him to sacrifice himself for fishermen he barely knew. "Why did he do it?"
From that question comes a resolution. Prof's been nothing but a juvenile deliquent, but that's going to change. Yet before he can do any good in the world, he finds himself in a jet plunging toward the ground and dying with regrets... (COTU 31)

Prof THINKS he's found a new calling - "to be the next Cousteau". He did work with Cousteau at one point aboard Calypso (and likely picked up some French), as seen in Secret Origins 12. There he had a near-death experience. But as fate would have it, Prof's REAL true calling was to become a Challenger.

Prof had many dangerous adventures before joining the Challs, as Villo and Brainex reveal with a time-scanner in COTU 52. Prof kills a shark, fights off enemy divers armed with flares and knives, and conquers his own fears when suffering rapture of the deep. He's hardly the weakest Challenger! As originally drawn by Kirby, Prof was skinny, even scrawny. Over time, and under the pen of Bob Brown, Prof bulked up, until his shoulders were almost as wide as the other guys'. Lately he's back to more realistic dimensions.

Shortly after joining the Challengers, he set a deep-diving record, as shown in Showcase 6.

Oh, and about Uncle Cyrus. Turns out, in Adventure 496, Cyrus is very much alive - and displeased with his nephew. Uncle Cyrus faked his death to dodge inheritance tax. The money should have gone to Cousin Freddie (never seen), to be returned to Cyrus. Unfortunately, grouses Cyrus, Nephew Mark is too honest to buy into the scheme. Cyrus, in fact, gets so incensed he assaults Prof with his cane and gets zapped by a broken lamp. Presumably Uncle Cyrus goes to jail. No word about Cousin Freddie. Prof have kept a good chunk of the fortune, after inheritance tax, because he bankrolls the Challs.

Prof also keeps a house somewhere in town near Challenger Mountain. He mentions in COTU 35 that the vision in the crystal ball is at "my place". Note that in the future Prof will need glasses. But who doesn't?

Early on Prof smoked a pipe. Incredible, when as a diver his life depends on his lung power. But many divers did smoke in the 1950s and 1960s. Later on he gave it up.