A left-handed hitter who threw right-handed, Franks attended the University of Utah. He broke into baseball with the Hollywood Stars of the Pacific Coast League in 1932, but he was soon acquired by the St. Louis Cardinals and joined their vast farm system. He made the Cardinals for just 17 games and 17 at-bats in 1939, before being drafted by the Brooklyn Dodgers, where he served as a second-string catcher in 1940-41 and began his long association with the Dodgers' manager at the time, Leo Durocher. After 3½ years of military service during World War II, Franks became the playing manager of the Dodgers' AAA St. Paul affiliate in the American Association in 1947. In August of that season, however, he resigned to resume his major league playing career with the Philadelphia Athletics, where he appeared in 48 games in 1947 and 1948 and batted .221.
In 1949 he received his first coaching assignment, as an aide to Durocher with the New York Giants. He was a member of two National League championship clubs and one World Series (1954) title team through 1955. According to author Joshua Prager in his 2006 book The Echoing Green, Franks played a critical role in the Giants' Bobby Thomson's famous pennant-winning home run in the 1951 NL playoffs -- Baseball's Shot Heard Round The World. According to Prager, Franks was stationed in the Giants' center-field clubhouse at the Polo Grounds, their home field, stealing the opposing catcher's signs through a telescope and relaying them through second-string catcher Sal Yvars (who was stationed in the bullpen) to the Giants' coaches and hitters. When asked where he was when Thomson hit his home run, Franks said, in 1996, that he was "doing something for Durocher" at the time.
Whatever his role may have been on that day, Franks was known as a devotee of Durocher-style, win-at-any-cost baseball, including intimidation through flying spikes and brushback pitching. Author Roger Kahn quoted Dodger outfielder Carl Furillo that Franks would poke his head into the Brooklyn clubhouse to taunt Furillo that Giant pitchers would throw at his head during that day's game. Furillo, whose hatred for Durocher was so intense that he would engage Durocher in a fistfight in the Giant dugout filled with enemy players, said of the Giants, in Peter Golenbock's book Bums, "They were dirty ballplayers ... They all wanted to be like Durocher, to copy Durocher. That Herman Franks, he was another one."
But when Durocher quit the Giants after the 1955 season, Franks left, too. From 1956-64, Franks was a Giants' scout, general manager of the PCL Salt Lake City Bees, then again a Giants' coach before succeeding Alvin Dark as the club's manager after the 1964 season.
Franks' four seasons (1965-68) as manager of the Giants, now based in San Francisco, produced four frustrating second-place finishes in the National League. The club won 95, 93, 91 and 88 games and finished 2, 1½, 10½ and 9 games behind the league champions. Finally, in October 1968, Franks stepped down as skipper and was replaced by Clyde King.
A successful businessman off the field, Franks spent the next eight years out of the major league spotlight, apart from a partial season (1970) as a coach under Durocher with the Chicago Cubs. In 1973 Franks was part of a group that attempted to purchase the New York Yankees from then-owner CBS, and in fact outbid the group headed by the eventual owner, George Steinbrenner.
After the 1976 campaign, Franks returned to the major leagues when he replaced Jim Marshall as manager of the Cubs. In 1977, he led the Cubs back to the .500 level, but the team lost ground in 1978 and was just one game above the break-even mark in September 1979 when Franks resigned. He was the interim general manager of the Cubs from May through November 1981 and offered to continue in the role permanently, but was passed over in favor of Dallas Green.
Although Franks compiled a poor record as a player (a batting average of .199 with three home runs in 188 games over parts of six seasons), he notched a winning record as a manager - 605-521, .537.