Half of one of the most successful comedy screenwriting teams in Hollywood, Ganz is the writing partner of Babaloo Mandel, both of whom frequently have collaborated with producer-director Ron Howard and producer Brian Grazer. As a team their feature credits include "Night Shift" (1982), "Splash" (1984), "Gung Ho" (1986), "Parenthood" (1989) and "A League of Their Own" (1992). With Billy Crystal, Ganz and Mandel have collaborated on "City Slickers" (1991) and its inevitable sequel "City Slickers II: The Legend of Curly's Gold" (1994), "Mr. Saturday Night" (1992) and "Forget Paris" (1995).

Ganz had a significant career in TV before his partnership with Mandel. A veteran sitcom writer and producer, he has created several series and written a number of pilots. Ganz's TV career began with a staff writer position on the classic comedy series "The Odd Couple" (ABC) starring Tony Randall and Jack Klugman. He eventually became the head writer on that successful series which initiated his relationship with Gary Marshall. Ganz also worked for many years as a supervising producer and writer on "Happy Days" (ABC) where he began his association with Ron Howard. He co-created the first spinoff of that series, "Laverne and Shirley"(ABC), and executive produced "Joanie Loves Chachi" (ABC, 1982-83), another "Happy Days" offshoot. Ganz was involved with several short-lived sitcoms and busted pilots that showcased well-known performers: "The Ted Knight Show" (CBS, 1978), "The Rita Moreno Show" (a 1978 pilot) and "Paul Sand in Friends and Lovers" (CBS, 1974-75). Writer-producer and college classmate Mark Rothman collaborated with Ganz on a number of TV series. With Babaloo Mandel, Ganz transferred several of their films to TV with limited success: "Gung Ho" (ABC, 1986-87), "Parenthood" (NBC, 1990) and "A League of Their Own" (CBS, 1993).

The screenwriting team took a story idea from comedian Billy Crystal and wrote the script for “City Slickers” (1991), a genuinely funny and sincere comedy about a middle-aged urbanite (Crystal) who’s convinced by his two best pals (Bruno Kirby & Daniel Stearn) to go on a cattle drive in rural Montana. High jinks, self-discovery and box office glory ensue. For their next project, they worked with Crystal on his directorial debut, “Mr. Saturday Night” (1992), a bland comedy-drama about a comedian whose self-destructive behavior keeps him from rising above his five-decade long mediocrity. With “A League of Their Own” (1992), a warm comedy about the formation of an all-female professional baseball league to fill in the gap left by men fighting in World War II, Mandel and Ganz scored a big hit artistically and creatively. Though bogged down by a maudlin second half, director Penny Marshall nonetheless crafted a funny and poignant film about an often neglected part of modern history.

After soft-peddling a potentially dark and satirical comedy, “Greedy” (1994), starring Michael J. Fox, the pair wrote the inevitable sequel, “City Slickers II: The Legend of Curly’s Gold.” The movie failed to capture the warmth and laughs of its predecessor, as well as box office dollars and Oscar gold. In another collaboration with Crystal, Mandel and Ganz penned the script to “Forget Paris” (1995), the actor’s second venture as director, which told the tale of an NBA referee who travels to Paris to bury his deceased father and meets an airline attendant (Debra Winger) whom he marries mere days later. After two relative box office failures—“Multiplicity” (1996) with Michael Keaton and “Father’s Day” (1997) with Robin Williams—the duo became two of many writers who worked on the screenplay for “Stuart Little” (1999), the story of a little mouse with a big heart who searches for a sense of belonging and a place to call home. The hybrid animation and live-action feature raked in a ton of box office cash and spawned the sequel, “Stuart Little 2” (2002), for which Mandel and Ganz were again uncredited for their work.

For their next project, the screenwriting team ventured into cultural satire—a different direction from their typical light comedy bent—with “EDtv” (1999), a remake of the French comedy, “Louis XIX – King of the Airwaves” (1993). Depicting an Everyman (Matthew McConaughey) whose world is turned upside down when his life is recorded on camera twenty-four hours a day for a foundering cable station, “EDtv” offered nothing that the more poignant and stylized “Truman Show” (1998) had already offered. After penning the sentimental coming-of-age drama, “Where the Heart Is” (2000), Mandel and Ganz spent the next few years performing uncredited rewrites. Then in 2005, they returned with two sharp hits: “Robots”, an animated adventure about an idealistic robot (Ewan McGregor) who travels to the Big City with the hope of making his clanky, mechanical world a better place, and “Fever Pitch”, a romantic comedy about a rabid Boston Red Sox fan (Jimmy Fallon) who finds his new relationship with a corporate executive (Drew Barrymore) suddenly deteriorating once baseball season starts.