Clint Eastwood's son, Scott Eastwood (credited under his birth name, Scott Reeves) appeared in the movie as Trey. Another son, Kyle Eastwood (who for many years was presumed to be his only son) provided the film's music score.
The "cool medal" the kids find in Walt's basement is the Silver Star, the U.S. Military's third-highest award for valor in combat. Despite its predominately gold color, it gets its name from the smaller silver star (based on the small silver World War I Citation Star) set inside the large gold star.
Eastwood's character is a Korean War veteran, which he has played in other movies such as Heartbreak Ridge (1986) and Absolute Power (1997). In real life, the actor's penchant for dropping ambiguous Korean War references is considered audacious by those who know him, because for his entire stint in the army he was a lifeguard at the Post Swimming Pool at Fort Ord in California. He never set foot in Korea.
According to Bee Vang, the Hmong actors for this film were isolated from the rest of the cast and crew. According to Vang, efforts by the Hmong actors to correct the portrayal of Hmong traditions were ignored. He has also refuted claims that the Hmong actors were encouraged to improvise. According to Vang, when he tried to improvise, Clint Eastwood told him to "stick to the script." Vang also stated that the cast and crew had attended a baseball game, but the Hmong actors were not invited. It was assumed that the Hmong actors were immigrants and did not know about baseball, but the majority of the Hmong actors were U.S. natives. Bee Vang later participated in a parody of the film, "Thao Does Walt," in which he played an elderly Hmong man to a teenage Caucasian boy, highlighting perceived racial stereotyping in the original scene.
Walt Kowalski's gun collection seems to consist of weapons he used in the military. His rifle is an American M1 Garand, a 9.5lb .30-06 gas-operated rifle. It was first issued during WWII, then re-issued in Korea before being phased out by the M14 selective fire .308 rifle. His pistol is an M1911A1, a .45 ACP semi-automatic handgun also issued during the Korean war.
In the original screenplay, Gran Torino (2008) is set over winter and spring. When Walt notices the Hmong cutting the chicken's head off, he spits in the snow. Thao is also pushed off a bike into the snow by the Latinos. It cuts forward three months to spring after this.
When Walt is at the Hmong neighbors' party, he pats the head of a young Hmong girl passing through, causing the family members to audibly gasp. As Sue then explains to him in the following scene, in the Hmong culture, the human head is believed to house the soul, and any touching of the head is believed to jeopardize this and is thus considered very disrespectful.
The famous scene where Walt points a rifle at the Hmong gang and says "get off my lawn" might be a possible homage to Eastwood's 1978 film Every Which Way But Loose in which Ruth Gordon's character points a rifle at the Black Widow gang and says "get off my porch."
Walt's death scene near the end of the film was supposed to signify the acting retirement of Clint Eastwood, since this is the only movie in which his character dies on screen. This held true for only four years, when the filmmakers of Trouble with the Curve (2012) convinced him to come out of retirement and star in the movie.
On Walt's birthday, before his family arrives, he reads his horoscope to his dog, Daisy. "Your birthday today...this year, you have to make a choice between two life paths. Second chances come your way. Extraordinary events culminate in what might seem to be an anti-climax." This could sum up the events of the film: Walt chooses between doing nothing or helping Thao when he is being harassed by his cousin's gang, the "second chances" could refer to leaving behind his racist attitudes (to some degree, at least) and spending time with Thao, Sue, and their family and friends? and, of course, the ending, where Thao and perhaps the audience may expect Walt to go out in a blaze of glory, instead of his self-sacrifice to have the gang members jailed for his murder.
At the end of this movie, just before Clint's character Walt is shot dead by the Hmong thugs, he asks, "Got a light?" This was the same line his character, Nick Pulovski, frequently asked in The Rookie (1990).