[3][7] After competing in singles, he began learning pairs and passing qualifying tests with partners from New South Wales and Queensland.

[5] Responding to a query from the Pachins, Russia-based coach Nina Mozer suggested a tryout between Ekaterina Alexandrovskaya and Windsor in Moscow.

[8] Observing the tryout, the coaches believed that the skaters would make a good match due to similar techniques and body types.

[11] Alexandrovskaya/Windsor made their senior debut in October 2016 at a Challenger Series event, the Finlandia Trophy; they placed sixth and obtained the minimum technical scores to compete at senior-level ISU Championships.

In December, the pair placed 5th in France at the JGP Final, to which they were called up as replacements for Russia's Ekaterina Borisova / Dmitry Sopot.

Ranked third in the short program and second in the free skate, they finished first overall, outscoring the silver medallists, Aleksandra Boikova / Dmitrii Kozlovskii of Russia, by 2.05 points.

Despite beginning the season with a bronze medal at the 2018 CS U.S. Classic, the move was unsuccessful, and both struggled with health and fitness concerns.

[20] Alexandrovskaya/Windsor placed ninth at the 2019 CS Nebelhorn Trophy, and then finished seventh at the 2019 Skate America, their lone Grand Prix assignment.

Following this partnership, Windsor suffered an ankle fracture after taking a hard fall on a jump attempt in practice.

Windsor briefly went to Sochi, Russia in May 2023 to work on his pair elements with Dmitri Savin and Fedor Klimov.

[26][27] In July 2023, it was announced that Windsor had teamed up with Canadian-born pair skater, Cho Hye-jin, and that they would be representing South Korea together.

[29] An ABC Television feature-length documentary film, Harley & Katya, detailing Alexandrovskaya/Windsor's relationship and partnership, was released in February 2022.