Joe Biden's first year in office could go down in history as a record-breaker on the job-creation front, with an explosion in hiring expected as the coronavirus vaccine rollout allows Americans to emerge from a year in hiding.

It may not be enough.

Only slightly more than half of the 22 million jobs lost in the pandemic were regained by the end of last year. Even if 2021 hiring shatters the post-World War Two record of 4.27 million jobs created in 1984, roughly a quarter of those who lost work could still be on the sidelines, with bleak prospects for regaining their vocations in an economy reshaped by the pandemic.

As Biden takes the oath of office on Wednesday, the job market awaiting him...