In 1980, Dunn made an ill-fated campaign for the United States House of Representatives in Louisiana's 4th congressional district. He lost to the eventual general election winner, Buddy Roemer, then of Bossier Parish and later the Democratic-turned-Republican governor of Louisiana from 1988 to 1992.
Dunn was born in Plain Dealing in northern Bossier Parish to George Forrest Dunn, Sr., and the former Gladys Malone. The senior Dunn was a native of Bradley, a village in Lafayette County (pronounced LA FAYE ETTE) in far southwestern Arkansas, located just north of the Louisiana boundary. He was an automobile mechanic. Two other Louisiana Democratic political figures also have roots in tiny Plain Dealing: former U.S. Representative Joe David "Joe D." Waggonner, Jr., and the late state Treasurer A.P. Tugwell.
Dunn attended Bossier High School, did not graduate, but obtained a General Equivalency Diploma in 1947. He served two years in the United States Navy, having been stationed aboard the U.S.S. Richmond. In 2009, Dunn was nevertheless named to the Bossier High School Hall of Fame.
While they were still teenagers, Dunn married the former Rachel Nelson (also born 1928). The couple had three children: Linda Dunn Turner (born 1947), Robby Jack Dunn (born 1949), and James Forrest "Jimmy" Dunn (1952–1985), who perished in an automobile accident in Oklahoma. The Dunns subsequently divorced, and Forrest Dunn married the former Donna Young (born 1943). The first Mrs. Dunn later married former state Senator Don W. Williamson, originally from Vivian in northern Caddo Parish, and later of Shreveport. Williamson was widowed from his first wife, the former Norma Herring of Vivian. Williamson, like Dunn, spent years in the furniture business. Dunn had two brothers, George Ellis Dunn (1939–2002) and James Wayne Dunn, who died in 2004.
Dunn was a salesman for Haverty's Furniture Store prior to launching Dunn Furntiure Company, which operated for three decades: 1955 to 1985. The main location was at 4001 Jewella Avenue in Shreveport, and a second outlet was launched on Line Avenue. Son Robby Dunn assisted in the store for a number of years and later ran a flea market. Dunn said that so many changes had occurred in the production, marketing, and sale of furniture over the years that it was "too much to mention."
Four years after the furniture store closed, Dunn accepted an appointment from the Republican Secretary of State W. Fox McKeithen, to head the state museum, which is located on the site of the Louisiana State Fair. As museum administrator, Dunn has worked to bring to Shreveport new exhibits of interest to a wide segment of the community, including an acclaimed display on Huey Pierce Long, Jr., and Earl Kemp Long.
Dunn is a member of the Downtown Shreveport Rotary International, one of the largest such clubs in the United States. He is a member of St. Marks' Episcopal Church on Rutherford Street in Shreveport.
Dunn's first venture in politics was his relatively brief tenure on the Caddo Parish School Board from 1969-1972. Ironically, Don Williamson had also served on the same school board, including a stint as its president. Williamson left the board to assume his legislative seat just as Dunn was beginning his board service.
Dunn was elected to the state legislature from District 3 in the 1971-1972 cycle, which also brought Edwin Washington Edwards to the governorship. He worked in the House with Senator Williamson to obtain four-year status for Louisiana State University at Shreveport. He fought to place Shreveport police and firefighters under the Louisiana state retirement system. He supported a successful constitutional amendment to require members of the Louisiana Board of Elementary and Secondary Education (BESE) to run at the same time, rather than with staggered terms.
Dunn called for an appointed state superintendent of education, an idea that came to fruition in the next session after he had left the legislature. He credited former Representative Alphonse J. Jackson of Shreveport, the father of Louisiana state Senator Lydia Jackson of Caddo Parish, with getting the bill passed.
Dunn said that he managed to acquire a popular water ride from the New Orleans World's Fair of 1984, but the City of Shreveport has never used it. Dunn said that he worked with Republican Governor David C. Treen to obtain six vans for the H.A.P. House on the Barksdale Air Force Base in Bossier City. The H.A.P. House provides special services for the handicapped.
Dunn also obtained state funds for a master plan for the Louisiana State Fair, held each fall in Shreveport, and a master plan and outlay plans for the museum which he administers.
One of Dunn's legislative colleagues was the late R. Harmon Drew, Sr., of Minden, the seat of Webster Parish. Drew's son, Harmon Drew, Jr., a judge of the Louisiana Court of Appeal for the Second Circuit in Shreveport, said that his father considered Dunn one of the hardest working and overall best legislators in Baton Rouge. Their terms coincided from 1972–1978, when the senior Drew returned to his previous post of Minden municipal judge.
Though he maintains Democratic affiliation, Dunn endorsed Republican President Gerald R. Ford, Jr., in the 1976 presidential election. In 1980, he ran for the Fourth Congressional District seat then held for a single term by former Representative Anthony Claude "Buddy" Leach, then of Leesville, the seat of Vernon Parish in western Louisiana. He finished fifth among the six candidates, including former state Senator Cecil K. Carter, Jr., of Shreveport, state Senator Foster Campbell of Bossier Parish, and state Representative Loy F. Weaver of Claiborne Parish.
The seat was won by Roemer, who unseated Leach in the runoff election, officially the Louisiana general election, which was held on the same day that Ronald W. Reagan unseated Democrat Jimmy Carter for the presidency. When asked about his congressional race, the tight-lipped Dunn said simply, "I did not get enough votes." He declined to support either Leach or Roemer in the second round of balloting. Dunn received 8,208 ballots (6.7 percent). As predicted by some Republicans, Dunn polled more than enough votes to keep the Republican candidate, James H. "Jimmy" Wilson of Vivian, from a first- or second-place primary finish, presuming that Dunn voters' second choice in most cases may have been Wilson because the two shared ideas of fiscal conservatism.
Dunn retired in 2010 from the administrator's position at the Louisiana State Exhibit Museum. He was succeeded by Wayne Waddell, who resigned from the Louisiana House of Representatives to accept the position. Dunn is now a registered Independent voter. He died on October 15, 2016.