It is believed she may have been a courtesan in the service of the Emperor, and that she entered into relationships with other men after the Emperor died, although that is, of course, speculation. What is not speculative is the exquisite quality of her poetry, which throbs with life and longing, and is quite complicated, given that it can be interpreted in several ways (both by readers in the original Japanese, since her words and images are subject to multiple meanings, and in translation).
Here is one of her most famous tanka, first in the Japanese, and then in translation three ways:
A life in vain.
My looks, talents faded
like these cherry blossoms
paling in the endless rains
that I gaze out upon, alone. (Peter McMillan)
The flowers withered
Their color faded away
I spent my days in the world
And the long rains were falling (Donald Keene)
the long rains falling on this world
my heart, too, fades
with the unseen color
of the spring flowers. (Jane Hirschfield and Mariko Aritani)
Here is a list that includes other possible translations of this same poem.
No matter how you read these translations, it's clear that the opening lines deal with a nature-based image (fading blossoms), while the remaining lines deal with her own fading beauty and passion during the "long rains". The metaphor is clear, and is a good example of how metaphor in tanka can and should work.
I love how startlingly fresh much of her language seems (depending, of course, on the translation involved) despite the passage of more than 1200 years. Others of her poems exhibit longing and loneliness in heart-aching, swoons-good language.
Ono no Komachi was not the only female among the foremost creators of tanka; she was followed in the 10th century by Izumi Shizibu, who is known to have been married twice, and to have been involved with two princes. Her work, like Komachi's, is worth seeking out. Shizibu's work manages to meld Buddhist sensibilities and eroticism.