Simon Bramhall, 53, used an argon beam machine to burn his initials on the organs of two anaesthetised victims in February and August 2013.
"What you did was an abuse of power and a betrayal of trust that these patients had invested in you," judge Paul Farrer told him at Birmingham Crown Court.
Bramhall was sentenced to a 12-month community order, meaning he will carry out 120 hours of unpaid work, and fined £10,000 ($13,650, 11,250 euros).
"Both of the (transplant) operations were long and difficult," Farrer said.
"I accept that on both occasions you were tired and stressed and I accept that this may have affected your judgement. This was conduct born of professional arrogance of such magnitude that it strayed into criminal behaviour.
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"I accept that you didn't intend or foresee anything but the most trivial of harm would be caused."
Another surgeon spotted Bramhall's initials on one of the livers. The branding was four centimetres (1.5 inches) high.
He told police it had been a misguided attempt to relieve the tension in the operating theatre.
Bramhall resigned from the Queen Elizabeth Hospital in Birmingham, central England, in 2014.
The consultant was given a formal warning by the General Medical Council professional body last February.
He now works for the state-run National Health Service in Hertfordshire, north of London.
The Queen Elizabeth Hospital said in a statement: "Mr Bramhall made a mistake in the context of a complex clinical situation and this has been dealt with via the appropriate authorities.
"There was no impact whatsoever on the quality of his clinical outcomes."
