Lukas was once a down-and-out thoroughbred whose lack of speed on the track meant another career was needed.
Lukas demonstrates his spelling ability.
However, it was not until owner-trainer Karen Murdock, of southern California, began to develop his more cerebral side that Lukas began to shine.
He is now an international equine celebrity and billed as the world's smartest horse. He receives more than 100 emails a day, but, being a busy horse and with no fingers, has minders who answer them on his behalf.
Lukas has now been officially recognised as the Guinness World Record holder for: "Most numbers correctly identified by a horse in one minute."
The 17-year-old met all the guidelines and identified 19 numbers in the time available.
Murdock had to meet a strict list of condition for the record to be considered.
Lukas' veterinarian, Dr Don Scott Vrono, assisted with overseeing the event.
Expert witnesses included Stacey Erb and Kathleen (Tat) Yakutis. Timers were Chuck Erb and Doug Murdock. Dawn Mellen, president of After The Finish Line, was also on hand.
Murdock said: "I'm very grateful for the help of so many good friends who have helped to bring this about. We're also very fortunate to have had the support of animal lovers all over the world who have sent encouraging messages and given us inspiration.
"I also want to express my appreciation to Guinness for their acknowledgement of Lukas' abilities and to Guinness talent manager Louise Ireland for her wonderful assistance."
What's next for the Guinness World Record Holder? Lukas plans to continue to share his message of hope and happiness for all creatures, Murdock says.
Will there be another record attempt in the future?
Lukas isn't about to let on, but word is he is practising identifying his shapes.
"For us, our goal has never been for personal recognition - what we're hoping to show is that animals are intelligent, so that they'll be treated better," Murdock says.
Lukas raced under the name Just Ask Mike. He left the track as a two-year-old with two bowed tendons after three unmemorable race finishes.
He changed hands several times and ended up emaciated and neglected in a back yard. He was rescued by a neighbor, Sue Smith, who took pity on the then eight-year-old chestnut gelding.
"You could see every rib and his tail was a solid bat of dried mud," she recalls.
Smith, a local trainer, had hoped to eventually include him in her amateur jumping programme.
After two years, however, he still wasn't fitting in, according to Smith, and Murdock purchased him after seeing his picture ad in the local Horsetrader publication.
"Working full-time as a psychiatric nurse, I had our (then) barn trainer begin some basic lessons on him, with the plan to take over myself and show him at lower level dressage shows.
"In a very short time Lukas became sullen and resistant to the point of being extremely dangerous - bucking, bolting and spooking (even in his own stall!)."
Several well-meaning observers suggested it was time to stop persevering with Lukas.
She agreed that after 30 years of training horses, she had just about met her match with Lukas.
"Before giving up, I decided to fall back on my many years of behavioural-training experience ... and also try to find out what he would enjoy doing.
"I set about un-training, by replacing unwanted behaviours with desirable responses.
"The particular responses that I chose to substitute happened to be tricks - fun and play being at the core of my system. I've always used the trick training games as a way to create a connection and build confidence, willingness, focus and trust."
Lukas responded to the training, laced with patience, kindness, affection and appreciation.
To date, his repertoire includes smiling, posing, nodding yes and shaking his head no, a dry and wet kiss, fetching, being "blindfolded", catching, yawning, saluting, pedestal work, a Spanish Walk (forward and backward), the stay and come, jambet (a three-legged pivot), curtsy, passage, bow, crossing his front legs, laying down while Karen sits on him, feet together (front and back), hide and seek (with his beloved green towel), acting lame, pushing a cart, and the rear.
Most of his acclaim, however, comes from his spelling, counting, identifying shapes and discriminating colours.
His clever equine exploits have seen him feature on NBC, CBS, ABC, CNN, and other media outlets around the world.
"His journey - which has really become a message of hope and happiness - has been in countless magazines, newsletters, blogs and newspapers world-wide," Murdock says.
"Our bond has attracted global attention as far away as New Zealand, and Lukas has over 5000 Facebook friends in almost every country.
"Lukas is listed on Yahoo, Google and the World Record Academy as 'The World's Smartest Horse'. All to show the happy results of gentle training and how wonderful and intelligent animals are.
"Children, especially, are part of Lukas' mission - his appearances are geared toward including families with an emphasis on responsible pet ownership.
"He is the official Spokeshorse for TROTT (Training Racehorses Off The Track) and a poster-boy for the California Thoroughbred Breeders' Association," she says.
"Horse rescues across the country have claimed him as their shining example and he's even been invited to Washington to lobby for legislation by the Humane Society.
"Many equine-assisted therapy groups have befriended him and he's associated with HEAL (Human-Equine Alliances for Learning) - a practice to assist trauma victims."
His proceeds and services are donated to help others, Murdock says.
He even has a book available on Lulu, as an e-book or in print, entitled "Playing With Lukas."
Aside from his appearances, his caregivers are busy responding to the more than 100 emails Lukas gets every day, many thanking the 16.2 hand for the inspiration he provided them.
"Now, if only I could teach him to answer his own mail!"