Seale had wanted to make "National Geographic" documentaries, but began his career as a camera assistant in the film department of the Australian Broadcasting Company in 1962. By the 70s, he was freelancing as a camera operator and first crossed paths with Peter Weir when he was hired as camera operator by cinematographer Russell Boyd on "Picnic at Hanging Rock" (1975). Seale went on to perform similar duties on Weir's "The Last Wave" (1977) and "Gallipoli" (1981). By then, he had graduated to director of photography, earning those stripes on the children's film "Deathcheaters" (1976). It was not until after working on several other Australian features, though, that Seale was tapped by Weir to shoot "Witness", which brought both to the USA. The cinematographer's flair for capturing the lyric qualities of the outdoors was tested and he certainly proved himself. Not only were the sequences of Amish farmers in their fields like movements on a warm quilt, but the barn-raising sequences possessed near poetic qualities. At the same time, when the evildoer is suffocated by corn cascading into a silo, the audience felt the noose of the grim reaper while simultaneously admiring with awe the majestic power of the corn.

Seale remained in the USA and was hired by Randa Haines for "Children of a Lesser God" (1986). He reteamed with Weir and star Harrison Ford for "The Mosquito Coast" (1987), again capturing the natural environment in such as way as to make it a character in its own right. The same was true of "Gorilla in the Mist" (1988); the cinematography helped explain why Dian Fossey (Sigourney Weaver) fell in love with the highland jungle. But it was Weir's "Dead Poets Society" (1989) where he displayed some of the best photography the screen has ever known. The idyllic, cloistered and protective world of the prep school boys was seen not just in the enveloping safety of the grounds, but in wonderful sequences in which Josh Charles was biking through field as birds fly away from his path. Another key sequence depicted the youths' initial decision to enter the woods to form the titular organization. Dressed in black school sweats, they run into the mist of night and disappear, as if leaving the known world for a more ethereal one from which one cannot return unchanged. Seale went on serve as director of photography for Haines' "The Doctor" (1991) and George Miller's "Lorenzo's Oil" (1992). He shot two films for Rob Reiner, "The American President" (1995) and "The Ghosts of Mississippi" (1996).

Seale has also directed one film, "Till There Was You" (1990), a visually stunning, but ineffectual thriller in which Mark Harmon's saxophone player is called to aid his brother in the South Seas. The cinematographer has also occasionally worked in TV, most often in programs shown on PBS, like two 1987 episodes of "Trying Times", "Drive, She Said" and "Get a Job", and the Australian-made "Top Kid" (1987), which aired on "Wonderworks".