The Bermudian was in danger of missing this afternoon's League Two clash against Torquay because of red tape.
But City have received clearance from the US Federation, allowing Smith to join Chris Sutton's squad for the clash against the Gulls.
The winger, who has signed a short-term deal, is now challenging Aaron Brown for a place on the left-hand side.
Imps boss Sutton was pleased to have the 28-year-old at his disposal after impressing since joining on trial last month.
"We've also added further depth to the squad with the arrival of Khano," wrote Sutton in his exclusive Echo column.
"He will be available for today's game after he received international clearance.
"From what we have seen of him, we like him.
"He will add something a little bit different and give us an extra dimension.
"He's played in the MLS which is a good standard."
Check out today's Lincolnshire Echo for Chris Sutton's exclusive column.