It was discovered 19 February 2009, by German amateur astronomer Erwin Schwab using a remote-controlled telescope at Tzec Maun Observatory (H10) in Mayhill, New Mexico, United States.

[1] On 25 December 2098, Milianleo is expected to pass 4,449,642 kilometers from the asteroid 704 Interamnia.

Milianleo is likely an X-type asteroid, based on its membership to the Aeolia family.

[6]: 23  When using a generic magnitude-to-diameter conversion, this asteroid measures approximately 1.6 kilometers in diameter, for an absolute magnitude of 16.5,[1][2] and an assumed visual geometric albedo of 0.17, taken from the Aeolia family's parent body.

[1][7] The approved naming citation was published by the Minor Planet Center 4 October 2009 (M.P.C.