On duty or at work. For example, Despite his illness he's determined to continue in harness. It also is put as be back in harness, meaning “to return to duty or work,” as in After a long vacation she's finally back in harness. This expression alludes to horses harnessed to perform work. [First half of 1800s] Also see die with one's boots on (in harness).
Words nearby in harness
How to use in harness in a sentence
This is a guy who has his son-in-law clean his eyeglasses, for crying out loud.
Her travel clique has been known to arrive at an airport, bags packed, passport-in-hand, within hours of spotting a deal.‘We Out Here’: Inside the New Black Travel Movement|Charlise Ferguson|January 4, 2015|DAILY BEAST
Earl Spencer adds, “Effectively, my great-grandfather sold his children to his father-in-law.”The Real-Life ‘Downton’ Millionairesses Who Changed Britain|Tim Teeman|December 31, 2014|DAILY BEAST
The lack of a gun is not likely to be a major problem for close-in air-to-air dogfights against other jets.
But those weapons are of limited utility, especially during close-in fights.
In fact, except for Ramona's help, it would have been a question whether even Alessandro could have made Baba work in harness.Ramona|Helen Hunt Jackson
Such throats are trying, are they not?In case one catches cold; Ah, yes!
The commander-in-chief still kept him attached to the headquarter staff, and constantly employed him on special service.
So far Murat had always held subordinate commands; his great ambition was to become the commander-in-chief of an independent army.
Their jurisdictions overlapped and the Gascon would play second fiddle to no one save to his great brother-in-law.