Mercedes Lackey says she was introduced to science fiction at the age 10 or 11, when she happened to pick up her father's copy of James H. Schmitz's Agent of Vega. She followed this with Andre Norton's Beast Master and Lord of Thunder, and continued to read all of Norton's works. She wrote for herself but without real direction or purpose until she attended Purdue University, where she took a one-on-one class of English Literature Independent Studies with a professor who was a fellow science fiction fan. He helped her analyze books she enjoyed and then use that knowledge. Mercedes then encountered fan fiction, which further encouraged her writing. She began publishing work in fanzines, and then discovered filk and had some filk lyrics published by Off Centaur Publications. Mercdes submitted a story to Sword and Sorceress, then sold the rewritten story to Fantasy Book Magazine. Her first sale was to Friends of Darkover.

Mercedes met C. J. Cherryh, who mentored her during the writing of her 'Arrows' series. During this time, Marion Zimmer Bradley included her short stories in an anthology and Cherryh helped Mercedes through 17 rewrites of 'Arrows'. During this time, she claims to have been writing so much that she had no social life at all.

Mercedes Lackey lives with her husband Larry Dixon outside of Tulsa, Oklahoma, in an unusual house, which she describes as a "2½-story concrete dome with an octagonal wooden shell over it to make it look more like a normal house... it's round with curved outer walls, which makes placement of furniture kind of awkward."

Mercedes and Larry Dixon have in the past worked in raptor rehabilitation. She often refers to her various parrots as her "feathered children". The afterwords to some of her books refer to rehabilitation and falconry, and it is clear that this interest has influenced and informed her writing. She also enjoys beadwork, costuming, and needlework. She claims, however, to be a "wretched housekeeper, and by and large an indifferent cook." Mercedes also does radar-reading during tornado season.

Lackey has been active in the filking community. She was a major contributor to an early album of space filk, Minus Ten and Counting. She has won 5 Pegasus Awards, mostly for her songwriting.

Music plays an important role in Mercedes’ writing, as she explains: "I frequently will write a lyric when I am attempting to get to the heart of a crucial scene; I find that when I have done so, the scene has become absolutely clear in my mind, and I can write exactly what I wanted to say. Another reason is because of the kind of novels I am writing: that is, fantasy, set in an other-world, semi-medieval atmosphere. Music is very important to medieval peoples; bards are the chief newsbringers. When I write the ‘folk music’ of these peoples, I am enriching my whole world, whether I actually use the song in the text or not."

Book series by Mercedes Lackey include:
Bardic Voices
Elves on the Road Universe:

• Bedlam Bard series (with Ellen Guon)
• Diana Tregarde series
• The Serrated Edge series (with Larry Dixon, Mark Shepherd, and Holly Lisle)

Elemental Masters
Halfblood Chronicles (with Andre Norton)
Heirs of Alexandria
The Obsidian Mountain Trilogy
Valdemar Universe:

• Heralds of Valdemar
• Vows & Honor
• The Last Herald Mage Trilogy
• The Mage Winds Trilogy
• Kerowyn's Tale
• The Mage Wars (with Larry Dixon)
• The Mage Storms Trilogy
• The Owl Mage Trilogy (with Larry Dixon)
• Valdemar Short Story Collections

A complete bibliography of Mercedes’ writing can be found at her personal website at http://www.mercedeslackey.com/.