The speaker of the poem is a devoted writer who deeply admires the Fair Youth. He believes in the enduring power of his own written words to outlive stone monuments, wasteful war, and death itself. He takes on the responsibility of creating a living legacy for the subject of his admiration, mocking the excessive tombs of kings in the process.

The Fair Youth is a beautiful young man who serves as the primary subject for the first 126 of Shakespeare's sonnets. He possesses a beauty that the poet considers worthy of eternal preservation. Though mortal and vulnerable to physical decay, he gains a form of immortality through the poetry written about him, destined to live in readers' eyes until the Last Judgement.

Time is personified as a destructive force that acts as the ultimate arbiter of life and death. It desecrates grand monuments built by men, erases history, and brings about physical ruin. Despite its formidable power to destroy physical objects, it cannot destroy the ideas carried within the written word.

The Dark Lady is the subject of the later sonnets in Shakespeare's sequence. She contrasts directly with the youthful man, introducing negative and complicated emotional dynamics into the poet's life. Both the poet and the Fair Youth eventually become involved with her, causing tension.

Mars is the Roman god of war. In the poem, he represents the physical destruction that human conflicts bring to the world. He overturns statues, roots out masonry, and burns cities, yet his destructive fire fails to consume the living record of the poem.