Lancaster, then Keystone manufactured watches featuring a patented "Dust Proof" design that used a small mica window to cover the only opening in the plate of the movement.

During World War II, Hamilton retooled its business model to serve the military, dropping its consumer products.

Some of the most collectible early Hamilton wristwatches include The Oval, The Tonneau, The Rectangular, The Square Enamel, The Coronado, The Piping Rock, The Spur, The Glendale, The Pinehurst, The Langley, The Byrd, The Cambridge, the Barrel "B", and The Flintridge.

Many models came in both solid gold and gold-filled cases, and, though rare, some wristwatches such as the Grant were made of sterling silver.

Naval Observatory had asked American watch manufacturers in 1939 to participate in domestically mass-producing chronometers.

Hamilton successfully perfected the mass production process and parts interchangeability maintenance method for these specialized timekeepers.

The Model 21 Hamilton Marine Chronometer for large vessels was built first and had a chain-drive fusee, the second hand advanced in 1⁄2-second increments over a 60-second-marked sub-dial, and was kept in a traditional gimbaled double box for the express purpose of keeping the clock in a "dial up" position to minimize ship-movement-induced timing errors.

In 1985, the British Ministry of Defence invited bids by tender to dispose of their mechanical Hamilton Model 21 Marine Chronometers.

[8] In 1955, Hamilton provided a "celestial time zone clock, permitting flight-type navigation" for the Astra-Gnome concept of what an automobile would look like in the year 2000.

[11] It was available in a variety of non-traditional asymmetrical case styles[12] including the Ventura that was designed by Richard Arbib.

The partnership was dissolved in 1965, with the remaining Hamilton-Ricoh electronic movements (marked "Ricoh 555E") re-cased as "Vantage" and sold in the U.S.[15] In 1966, Hamilton acquired the Buren Watch Company of Büren an der Aare, Switzerland, including all factories and technologies Buren had developed up to that point.

This design allowed for a substantially slimmer automatic watch that still retained a center sweep second hand.

By 1972, the Buren-Hamilton partnership was dissolved, and the factory liquidated, due to decreased interest and sales of the Hamilton-Buren product.

[22][23] In the film, John David Washington also wears a steel Hamilton Jazzmaster Seaview Chronograph.

[24] Hamilton watches and clocks have appeared in the films Shanghai Express (1932) starring Marlene Dietrich, Interstellar (2014), The Frogmen (1951), 2001: A Space Odyssey (1968),[25] The Talented Mr. Ripley, King of the Hill (1993 film), Ocean’s 8, The Martian, Independence Day, Pearl Harbor and A Good Day to Die Hard, as well as TV shows Mad Men and Jack Ryan.

[27] Notable presenters and winners have included Sean Baker, Amy Poehler, Hans Zimmer, Pamela Anderson, Elle Fanning,[28] Viola Davis, Rian Johnson, Jordan Peele, Frankie Faison,[29] Ryan Gosling, Rosamund Pike, Jake Gyllenhaal,[26] Maggie Gyllenhaal, Kristen Stewart, Regina King, Mahershala Ali, Jamie Dornan, Peter Sarsgaard, Awkwafina, Kelly Marie Tran, Javier Bardem, Denis Villeneuve, Simon Rex, Kirsten Dunst, Ann Dowd, Martha Plimpton, Reed Birney, Jason Isaacs and Marlee Matlin.