Can a sponsorship undertaking be discharged early if the sponsored person becomes a Canadian citizen?

No, a sponsorship undertaking is generally not discharged early just because the sponsored person becomes a Canadian citizen. Citizenship changes the sponsored person's legal status in Canada, but the undertaking itself is a separate promise made by the sponsor to the government, and it generally continues to run for its full length regardless of that status change.

This surprises many sponsors, who understandably assume that once their family member becomes a citizen, their financial responsibilities are finished. In reality, the undertaking exists partly as a mechanism for the government to recover certain social assistance paid to the sponsored person during the undertaking period, and that purpose doesn't disappear simply because the person has gained citizenship. Unless there's a specific IRCC policy in place that says otherwise, the undertaking generally keeps running on its original timeline.

Because policy in this area can be updated, it's worth confirming the current rules directly rather than assuming automatic discharge based on citizenship. If you're a sponsor whose sponsored family member has become or is becoming a Canadian citizen and you have questions about your ongoing obligations, speak with an immigration lawyer to get an accurate, up-to-date picture of where things stand for your specific situation.