The galaxy was found using the Hubble Space Telescope and was dubbed z8_GND_5296. The Keck Observatory in Hawaii later confirmed its distance.
"This is the most distant galaxy we've confirmed," said lead researcher Steven Finkelstein, from the University of Texas at Austin. "We are seeing this galaxy as it was 700 million years after the Big Bang."
Astronomers were able to determine the galaxy's distance by analyzing light displacement that appears as a change in color, and found the galaxy has a redshift of 7.5.1.
The galaxy is believed to be small -- about one or two percent the mass of the Milky Way -- and is rich in heavier elements.
"One very interesting way to learn about the universe is to study these outliers and that tells us something about what sort of physical processes are dominating galaxy formation and galaxy evolution," Finkelstein said.
"What was great about this galaxy is not only is it so distant, it is also pretty exceptional," he added.
One of the most surprising features of z8_GND_5296 is its fast-paced star production.
"This high star-formation rate maybe is a clue as to why these galaxies can form so quickly," said Dr. Marek Kukula, a Public Astronomer at the Royal Observatory Greenwich.
The study regarding the new galaxy will be published in the journal Nature on October 24.