Clark Savage, Sr was the father of Doc Savage in the novels published under the house name of Kenneth Robeson. He dies in the first book, The Man of Bronze.
The elder Savage became a widower shortly after his son's birth, and subsequently arranged for his son to be trained by teams of experts, from infancy, with a view to inculculating in the child near-superhuman strength and intelligence - notably, with little female contact.
A number of scholars have noted the similarity between the Savages and the protagonists of the novel The Savage Gentleman by Philip Wylie, published after the events of The Man of Bronze but before any Doc Savage adventures came out. In Wylie's novel, a mysognistic newspaper publisher named Stone deliberately shipwrecks himself and his infant son, in order to bring up the child as the perfect newspaperman and late-Victorian gentleman.
In Tarzan Alive, Philip José Farmer identifies the elder Savage with James Wilder, the illegitimate son of the Duke of Holdernesse or Greyminster (i.e. the sixth Duke of Greystoke). Savage's baptismal name is given as "James Clarke Wildman", and his mother is identified as Patricia Clarke Wildman. Farmer also names Savage's wife - Doc Savage's mother - as Arronaxe Larsen. Although neither Tarzan Alive nor Doc Savage: His Apocalyptic Life make any reference to The Savage Gentleman, it is interesting to note that in Wylie's book Stone's bizarre behaviour is the direct result of his being abandoned by his wife, Nellie Larsen.
Farmer inserted references to the adventures of Clark Savage, Sr. in his translation and expansion of the novel Ironcastle by J.H. Rosny.
In the Doc Savage comics mini-series Doom Dynasty, Clark Savage, Sr is identified as the son of Richard Henry Savage, occasionally cited as the inspiration for Doc Savage himself.
Timothy J. Rutt's Wold Atlas article The First Doc Savage: The Apocryphal Life of Clark Savage, Sr, notably identifies Clark Savage, Sr as Daniel Hardin, a character from another Wylie novel, Gladiator.
Arthur C. Sippo's article Further Thoughts on the Doc Savage Chronology gives considerable thought to the life of Doc's father - research continued in his blog. Both he and Brad Mengel (in the latter's article What's in a Name?) give thought to reconciling Farmer's geneaology with Doom Dynasty.