The 29-year old was a short-term injury replacement player at the Fury this season but has returned home to Scotland where he will team up with the Staggies for the remainder of the season.
Smith adds Ross County to a long list of former clubs including Wycombe Wanderers, Reading, Hearts, Livingston, Sheffield United, Swindon Town, Bristol City, Dundee United and Carlisle United among others.
Ross County manager Derek Adams said the signing of Smith would be very valuable to the team.
"We've got a hectic time ahead of us with four league games to be rescheduled and the club's first ever Scottish Cup quarter-final to prepare for, meaning we face the prospect of up to eight games in four weeks," said Adams.
"As everyone knows we're working with a limited budget and a small squad which that sort of fixture pressure will really test, so I'm delighted we've managed to bring Grant in to strengthen the squad.
"He's a very experienced player who is comfortable in a number of positions and adds something different to the squad we already have in place, which is exactly what we need."