"[3] A native of China, Thomas emigrated to the United States at thirteen and learned English reading romance novels.

[7] Thomas found English-language romance books interesting due to their departure from Chinese cultural understandings of courtship.

Reviews were generally favorable, and Romantic Times named it as one of the Innovative Historical Romance nominees for 2009 and noted the "musical quality" of its prose.

The New York Times said "The Chinese-born Thomas is known for a lush style that demonstrates her love of her second language, and this novel edges into historical fiction with its transporting prose even as it delivers on heat and emotion and a well-earned happily ever after".

"[2][23][24][25] In the fall of 2013, Thomas branched into writing young adult fantasy books, and Publishers Weekly said of The Burning Sky: "As expected, Thomas’s romantic touch is sure, but she is just as adept with fantasy world-building, carrying the banners of Anne McCaffrey and Caroline Stevermer, among others, in a wonderfully satisfying magical saga".

Kirkus Reviews said The Burning Sky "bids fair to be the next big epic fantasy success",[27] but said of The Perilous Sea: Themes of identity and memory, destiny and choice tie together the two stories, told in alternating chapters with ubiquitous cliffhangers.

When the storylines finally intersect, the resolution is so abrupt as to be almost anticlimactic; but the dramatic, defiant conclusion will stoke anticipation for the next volume.

[30] The release of The Hidden Blade and My Beautiful Enemy in the summer of 2014 marked a departure from her traditionally-set historical romances with these set in imperial China.

In an interview on Kirkus, she revealed that she had written My Beautiful Enemy before she was published, intending it to be a series spanning twenty years.

"[6] It received mixed reviews, with NPR calling it "a bold new direction for Thomas, yet maintains the emotional intensity she is celebrated for".

[31] Kirkus Reviews felt the villain was its main weakness, but that its complex characters was its strength and called it "[a] thought-provoking exploration of gender roles in the East and West and in the historical romance genre.

[33] In its original starred review, it said With incisive character development, deft pacing, and lyrical, nearly poetic prose, Thomas transports readers between remote, breathtaking Chinese Turkestan and teeming late Victorian London.

Thomas once discussed the challenges of writing in an historical setting other than Regency England: If I just said the Northwest Frontier of British India or Chinese Turkestan, most people would be drawing a blank.

I adore that it was a time of tremendous advances in scientific understanding and technological capability—in Private Arrangements, for example, there is an automobile—and yet people still lived under a formality that is exotic and almost incomprehensible to us here in 21st-century America.

That formality sets off a wonderful tension for a writer to explore the sexual charge in a look, a word, a hand held a fraction too long.

She studies how authors like Laura Kinsale, Courtney Milan, Judith Ivory, Ariana Franklin, and Laurie R. King integrate historical world-building into their narratives.

Thomas's writing is often described as lyrical, lush, musical, graceful, rich, evocative, with unique metaphors and turns of phrase.

Author Kiersten Hallie Krum asserted that Thomas, along with Joanna Bourne and Meredith Duran, make up the forefront of a new wave in historical romance fiction strong in lyrical prose.

Her unique word choice is that one step to the left that eschews the boring in favor of the unexpected; "unsighted" rather than the mere "blind" or "a high castle wall of a smile," wholly original and yet instantly recognizable.

The cadence of her sentences seduce a reader as surely as any romantic hero until you want to lay down on the nearest flat surface and simply succumb as her prose takes you, Calagon-like, away.

[20][39][40] "Perhaps unrequited love was like a specter in the house, a presence that brushed at the edge of senses, a heat in the dark, a shadow under the sun."

[41][42] Luckiest Lady in London contains strong themes of how women in Victorian England are under immense pressure to meet high ideals that can have disastrous consequences.

— Mia Marlowe[46] "I used to dread starting a new Judith McNaught novel because I was confident it would rip my heart from my chest but was likewise knew the HEA denouement would be well worth the agony.

- Kiersten Hallie Krum[38] She has received starred reviews for several titles from Booklist, Kirkus, Publishers Weekly, and Library Journal and as of 2015, has finaled four times in RITA Award contest.