The 29-year old defender joined the Bairns this summer from Greenock Morton and will now wear the captain's armband for the coming season.
Buchanan, who was brought up and schooled in the town, was with the Bairns till the age of 16 before departing the club.
He began his senior career with Armdale Thistle and went on to represent Bathgate Thitslte, Airdrieonians, Dunfermline, Dumbarton, St Mirren and Livingston before his move to Cappielow.
Speaking on the appointment, Falkirk manager Ray McKinnon comented: “Growing up and living in the area Gregor is a local boy and knows exactly what the club means to the people of Falkirk.
“He has terrific leadership qualities on the pitch, but he’s also a fantastic leader behind the scenes.
"There is already a great buzz in and around the dressing room with everyone gelling together very quickly.
“Gregor has earned this position, he deserves it and I am sure he will be an outstanding captain this season.”