2020: two-year-old season Kyprios began his racing career in an eight and a half furlong
maiden race on
heavy ground at
Galway Racecourse on 8 September when he started at odds of
9/4 in a seven-runner field. Ridden by
Seamie Heffernan he settled just behind the leaders before producing a sustained late run to take the lead in the final strides and win by three quarters of a
length from Lifetime Legend. A month later the colt was sent to England and moved up sharply in class to contest the
Group 3 Zetland Stakes over ten furlongs at
Newmarket Racecourse. With Moore in the saddle he started favourite but never looked likely to win and came home sixth of the eight runners behind Lone Eagle, beaten more than sixteen lengths by the winner.
2021: three-year-old season On 23 April Kyprios began his second season in the Blackwater Race over ten furlongs at
Cork Racecourse when he was ridden by Heffernan and started the 15/2 fourth choice in a six-runner field. In a rough race, Kyprios hung to the right in the straight, recovered after being bumped by a rival, gained the advantage a furlong out and won by half a length from O'Reilly. Moore, who would ride Kyprios in all his subsequent races, was in the saddle two weeks later when the colt was sent to England for a second time and started 7/2 second favourite for the
Novibet Derby Trial Stakes over one and a half miles at
Lingfield Park. He was in contention for most of the way but faded in the closing stages and finished fourth, ten lengths behind the winner Third Realm. Kyprios was sent to
Royal Ascot to contest the
Queen's Vase over fourteen furlongs but was withdrawn from the race after becoming distressed and breaking out of the
starting stalls. He sustained bad bruising to his back and missed the rest of the season.
2022: four-year-old season Kyprios began his third campaign in the
Listed Vintage Crop Stakes over fourteen furlongs at
Navan Racecourse on 23 April when he was ridden by Moore and started the 5/1 second favourite behind his older sister
Search For A Song in a nine-runner field which also included Baron Samedi (
Belmont Gold Cup Stakes) and Leo De Fury (
Mooresbridge Stakes). Kyprios settled in second place behind the pacemaker Effernock Fizz before taking the lead inside the last quarter mile and after repelling a challenge from Search For A Song he drew away in the closing stages to beat his sister into second place by two and three quarter lengths. After the race O'Brien said: “We always thought he was going to be very nice. He went to Ascot last year and jumped out under the stalls and he hasn’t run since then. He looks like a stayer with a bit of class, he relished that trip. We liked him a lot last year and he has done well since then. He relaxes and he quickens." On 13 May only three horses appeared to oppose Kyprios when he started at odd of 1/10 for the
Group 3 Saval Beg Stakes over fourteen furlongs at
Leopardstown Racecourse. With Moore in the saddle he led from the start, drew away in the last quarter mile and won by fourteen lengths from the five-year-old Sunchart. O'Brien's representative Chris Armstrong commented "Aidan is very happy with him. He’s progressing nicely this year and has stepped up again from his last run. It was always the plan to go Navan, then here for the Saval Beg and head on to the Gold Cup at Ascot. It’s a tried and tested route so hopefully he follows in the footsteps and fingers crossed the next stop will be Ascot... His last furlong was probably his best. He was out in front and probably a bit idle but he really stretched in the last furlong." The 2022 edition of the
Ascot Gold Cup was run over two and a half miles on good to firm ground at Royal Ascot on 16 June and Kyprios, ridden by Moore, started the 13/8 favourite. His eight opponents were headed by
Stradivarius and also included
Princess Zoe, Mojo Star (runner-up in the
Epsom Derby), Burning Victory (
Triumph Hurdle) and Bubble Smart (
Prix Gladiateur). Kyprios settled in mid-division as the outsiders Earlofthecotswolds and Tashkhan set the pace, before moving to the outside and making progress approaching the final turn. He took the lead two furlongs from the finish and fought off a sustained challenge from Mojo Star to win by half a length, with Stradivarius a further three quarters of a length back in third place. Aidan O'Brien said "We think he's a horse who is going to come forward again. He's brave, genuine and a great horse. Ryan gave him a marvellous ride and had belief in him. When he really wanted him, he answered." Moore said that the horse had not been suited by the slow pace commenting "It wasn't a nice race to ride. I didn't like the spot we were in as we were going slow. They were getting an easy time up front and I had to move him to the outside – I don't like doing that. We got going and got to the front, and when Mojo Star has come to us, that's when he's clicked in. It wasn't a true test today but he was much the best and there will be lots of good days with him." In November 2022, he received the
Cartier Racing Award for European top stayer of the year. ==2023: five-year-old season==