With a satiric tone, Auden employs verbal irony in his poem. The title itself is ironic: Alluding to the Unknown Soldier--any of those soldiers killed in World War I who were unidentifiable--that have been honored by a monument to them for their valor in battle, JS/07/M/378 is ironically compared. But, he does have an identification number and was alive within his country where people should have known who he is. And even though he is "unknown," and has done nothing to draw attention to himself, he is, ironically, the most respected.
Also ironically, the Unknown Citizen is a hero because he has done nothing out of the ordinary: He has gone to war when drafted; he has worked at an automobile manufacturer and belonged to the union; he has bought the daily paper; he purchased things on the Installment Plan; he has held politically acceptable opinions and has never contested educational policies.
With another contrast to what is expected, the rhyme is unbalanced in Auden's poem, producing the hint of something wrong. Certainly, the last two lines make use of Auden's verbal irony that prevails throughout his poem:
Was he free? Was he happy? The question is absurd:
Had anything been wrong, we should certainly have heard.
Clearly, Auden satirizes the expectation of conformity in modern life and social organization. The lackluster life of the citizen, whose name is dispensed with and replaced with a mere number is ironically honored with cold marble; moreover, the man with no name is termed "a saint" for relinquishing his individuality and identity.