[6] Kwiatkowski is seen as a strong all rounder, with good sprinting, time-trialling and climbing abilities allowing him to win both stage races and one day classics.

He turned professional in 2010 with Caja Rural and in 2011 joined Team RadioShack, and placed third overall in the Driedaagse van West-Vlaanderen, the Three Days of De Panne and the Tour du Poitou-Charentes.

Kwiatkowski then rode a strong classics campaign, placing fourth in the Amstel Gold Race and fifth in La Flèche Wallonne.

With a strong time trial, he was able to regain the white jersey of the young rider classification on Stage 11, but lost the lead shortly after to Nairo Quintana.

In September, he grabbed the leader's jersey of the Tour of Britain by winning the fourth stage in a select group sprint of 6 riders.

[19] On 25 March 2016, Kwiatkowski won his first cobbled classic, E3 Harelbeke, by outsprinting Peter Sagan after the pair broke away from an elite group with 30 kilometres (19 miles) remaining.

[20] He was named in the startlist for the Vuelta a España,[21] After Team Sky won the opening time trial, Kwiatkowski took the race leader's red jersey after finishing fourth on stage 2.

[22] This marked a culmination of a difficult season for Kwiatkowski, after illnesses earlier in the year had wrecked his Ardennes classics campaign and led to him missing out on selection for the Tour de France.

On 16 April, Kwiatkowski took second place in the Amstel Gold Race after being defeated by Philippe Gilbert (Quick-Step Floors) in a two-up sprint finish.

On 29 July he won Clásica de San Sebastián, outsprinting Tony Gallopin, Bauke Mollema, Tom Dumoulin and teammate Mikel Landa in a five-man sprint finish.

[27] At the Volta ao Algarve in February 2018, Kwiatkowski, whilst sitting second overall behind teammate Geraint Thomas, was part of a 31-man breakaway which went clear in the opening kilometres of the final stage.

Thomas suffered a mechanical issue 1.5 kilometres (0.93 miles) from the summit of the final climb to Sarnano–Sassotetto, that resulted in him losing 34 seconds and the overall leader's blue jersey to Kwiatkowski.

[30] In July Kwiatkowski again played a supporting role for Team Sky at the 2018 Tour de France, helping Thomas to win the race overall and Chris Froome to finish third overall.