Before filming begins, the key grip attends location scouts and meets the Director of Photography to determine what additional tools (location-specific motor vehicles, dollies, cranes, mounts, etc.) will be needed, orders and preps required equipment, and transports equipment to the filming location. Once on set, the key grip coordinates with the electric and camera departments alongside the Director of Photography to control lighting and camera movement and setup. As a supervisor, the key grip directs the crew of grips, many with specialized skills such as dolly grips, crane operators, or special equipment operators. The key grip is sometimes credited as the "first company grip."
Additionally, the key grip is frequently asked to be the safety monitor of the film set. However, changes in the film and television worlds have created lasting change in crew responsibilities. Any union production crews working under the "Hollywood" umbrella are now required to take Occupational Safety and Health Administration-style certified courses in safety. The First AD (first assistant director) is responsible for the safe operation of the set. The Key Grip no longer has that distinction in the newer Hollywood policy.
In Great Britain the "grips" are part of the camera department exclusively and are not generally responsible for regular grip duties as they are in the United States. In Australia and New Zealand the key grip generally owns the grip equipment, often consisting of dollies, track, cranes, camera cars, and insert trailers.