Are there exemptions to the non-resident speculation tax for people already working in Ontario?

Not simply because you are working here - employment status on its own is not one of the recognized exemption categories for Ontario's Non-Resident Speculation Tax. A foreign national who is working in Ontario on a valid work permit is still generally subject to the tax on a residential purchase unless they separately qualify under one of the actual exemption or rebate pathways, which are narrower and tied to immigration status rather than employment.

Those recognized pathways include being nominated under the Ontario Immigrant Nominee Program, being a protected person, purchasing jointly with a spouse who is a Canadian citizen or permanent resident, or becoming a permanent resident yourself within a defined window after the purchase, which can support a rebate. None of these turn on simply holding a job in the province, however long you have worked here.

If you are working in Ontario and considering a purchase, look specifically at whether you fit one of these defined categories, rather than assuming your employment history itself provides relief, and confirm current eligibility with a lawyer before you buy.