The first portion of the roadway that is signed as SR 109 today was designated on April 7, 1933 and makes its first appearance in August 1933. It was unimproved but maintained and measuring 19.2 miles (30.9 km) and went between US 29/SR 14 in LaGrange to SR 41 in Greenville. In October 1933, a small portion near Greenville underwent some type of construction. In January 1935, SR 109 underwent construction from Greenville to the Meriwether–Troup county line. Finally in October 1935, the entire length between Greenville and LaGrange was under construction. In April 1937, an unimproved but maintained section measuring 17.1 miles (27.5 km) travelled in an arc between the Alabama state line and US 29/SR 14 just west of LaGrange. Finally in January 1938, the Meriwether County section of 109 was graded but not surfaced. with the entire Greenville–LaGrange section being graded by September 1938. A small section between US 29 and the Chattahoochee River was under some type of construction also at that time. By 1938, the future Pike County sections of SR 109 were built as was the Greenville-Gay section by, 1939 but none of these sections would be designated until later. The Greenville–LaGrange section was the last upgrade in the 1930s being finally hard surfaced in January 1940.
On September 25, 1940, a third section of SR 109 measured 9.2 miles (14.8 km) was listed as unimproved but maintained was designated where modern day SR 109 Spur runs, between Greenville and Gay and became hard surfaced by April 1941. In 1944, a fourth section 10 miles (16 km) long was designated between Molena and SR 3 in Pike County and by 1945 a small section of it was hard surfaced. Also in 1945, a portion of the second section of SR 109, between US 29/SR 14 and the Alabama state line, was hard surfaced from US 29/SR 14 to just past the Chattahoochee River near the future intersection of SR 244. North of this point to the Alabama state line was only a type of stabilized earth. In April 1949, the Greenville–LaGrange section of SR 109 was designated a principal state route.
Between January 1952 and September 1953, the section between SR 244 and the Alabama state line was graded but not hard surfaced along with the western half of the section between Molena and US 19/SR 3 while the eastern half of this section was hard surfaced. Also in 1952, SR 109 was shown designated throughout its entire Pike County routing; from SR 18 east of Molena to SR 18 near Barnesville. The eastern leg designation wouldn't show on state maps until 1960. The western half of this section was hard surfaced by June 1954. Between June 1955 and July 1957, more of SR 109 was hard surfaced from SR 244 to just north of the Heard–Troup county line. Also, the stretch between Greenville and LaGrange was no longer designated a principal state highway. By June 1960, SR 109 was hard surfaced and designated on state maps for its entire length from the Alabama state line to its current terminus with SR 18 near Barnesville. No recorded changes were made until 1971.
In 1971, SR 109 begins to closely resemble the modern routing of the route. With the West Point Dam under construction, the 1971 route of SR 109 would soon be underwater which followed modern day Antioch Road and Old Roanoke Road. Thus the short-lived SR 701 and SR 701 Spur was marked under construction as a path over the future lake. In 1975, SR 701, its spur, and West Point Dam were completed as well as the SR 109/I-85 interchange was under construction to be completed in full by 1978.