How is one reborn as a chakravartin? Chakravartin (Sanskrit cakravartin, Pali cakkavattin) is a Sanskrit
  term used to refer to an ideal universal ruler who rules ethically and
  benevolently over the entire world. Such a ruler's reign is called
  sarvabhauma.


How does one achieve such a venerable state ?
I think that what is taught to children about a &quot;universal monarch&quot; -- together with The Legendary Account of the Four Sights, in the Introduction to the Jâtaka -- is that the prince Siddhattha might have been one (and that his father wanted him to become a ruler), and that he chose not to be:

Seven of these raised two fingers each, and gave a double interpretation, saying, &quot;If a man possessing such marks and characteristics continue in the household life, he becomes a Universal Monarch; if he retire from the world, he becomes a Buddha.&quot; And then they set forth all the glory of a Universal Monarch.
But the youngest of them all, a youth whose clan-name was Kondañña, after examining the splendid set of marks and characteristics on the person of the Future Buddha, raised only one finger, and gave but a single interpretation, saying, &quot;There is here naught to make him stay in the household life. He will most undoubtedly become a Buddha, and remove the veil of ignorance and folly from the world.&quot; For this Kondañña was one who had made an earnest wish under former Buddhas, and was now in his last existence. Therefore it was that he outstripped the other seven in knowledge, and saw but one future; inasmuch as a person possessed of such marks and characteristics would never stay in the household life, but would undoubtedly become a Buddha. So he raised only one finger, and gave that interpretation.

So at least one of the requirements for that &quot;achievement&quot; is to &quot;stay in the household life&quot;.

Wikipedia says,

The first references to a Chakravala Chakravartin appear in monuments from the time of the Maurya Empire (322–185 BCE), dedicated to Chandragupta Maurya and his grandson Ashoka. In Buddhism, the Chakravarti came to be considered the secular counterpart of a Buddha.

I guess that the conceit (of comparing &quot;universal monarch&quot; and &quot;Buddha&quot;) might have been consolation and/or flattery for the emperor, or perhaps just good advice for the emperor.
The biographies (including birth, achievements, etc.) of Chandragupta Maurya and of Ashoka are also linked on Wikipedia -- see especially Conquest of Kalinga &amp; Buddhist conversion but also Buddhist kingship.