The 31-year-old former Motherwell, Ross County and Stenhousemuir player joins the Bully Wee after five seasons at Forthbank.
Smith netted 25 goals in 2017/18 and was named PFA Scotland League 2 Player of the Year then scored 11 times in 2018/19 despite missing the early months of the campaign through injury.
He follows Annan Athletic winger Chris Johnston in moving to Danny Lennon's team, who will be playing in Ladbrokes League 1 next season.
