Determinator/Poetry

• "Invictus" by William Ernest Henley embodies this trope.
• Rudyard Kipling's poem "The Overland Mail" portrays a postman in India as this, in terms that make "neither rain nor snow nor glo m of ni t" seem kind of mild (bear in mind the poem specifically states he's doing all this at night ... in the jungle ... uphill):

Is the torrent in spate? He must ford it or swim.
Has the rain wrecked the road? He must climb by the cliff.
Does the tempest cry halt? What are tempests to him?
The service admits not a "but" or an "if."
While the breath's in his mouth, he must bear without fail,
In the Name of the Empress, the Overland Mail.

• • Also, in his poem, "If-"

If you can make one heap of all your winnings
And risk it on one turn of pitch-and-toss,
And lose, and start again at your beginnings
And never breathe a word about your loss:
If you can force your heart and nerve and sinew
To serve your turn long after they are gone,
And so hold on when there is nothing in you
Except the Will which says to them: "Hold on!"

• "Epitaph on an Army of Mercenaries" by A. E. Housman invokes this, referring to the British Army in World War I. (Apparently the German press had been saying that the British soldiers, professionals rather than conscripts, should be considered mercenaries.) "What God abandoned, these defended" -- you can't get much more Determinator than that.
• As the page quote for the main page suggests, Ulysses (or Odysseus, if you prefer) is definitely one, whether in Alfred Lord Tennyson's Ulysses or in Homer's The Iliad and The Odyssey.
• Subverted with the Shel Silverstein poem, "The Little Blue Engine"