With the immense success Omega saw from the Speedmaster Professional series, especially after its iconic trip to the moon, they decided the expand the Speedmaster model with the ever-evolving Mark series of chronographs. The Mark II debuted in 1969 with a bold, sunburst-finished tonneau-style case. The Mark III was introduced in 1971 and was the first Speedmaster to employ an automatic winding movement using the Lemania cal. 1340. The Mark IV was introduced in 1973 and melded the Mark II case style with the same Lemania-based movement of the Mark III. After a short hiatus, Omega created the Mark V which featured a very evolved aesthetic that many refer to as 'futuristic'.

The Speedmaster MARK II came with the same Lemania-based movement as the original Speedmaster Professional "Moonwatch", reference 145.022. This watch contains Omega’s original caliber 861 movement and was in production from 1968 and lasted until 1996 when Omega introduced the Caliber 1861 movement. Unlike the Speedmaster Professional, the Omega Speedmaster MARK II has a barrel-shaped case that has polished chamfers and a brushed top and sides, giving it a different look from the standard Speedmaster Professional case worn by NASA Astronauts. The classic timing scale that the Speedmaster is known for is also different; it is under the mineral glass crystal and not externally located on the outside of the crystal as an external bezel, in essence, protecting the timing scale from scratches or disruption. Unlike modern timepieces with scratch-resistant sapphire crystals, pieces of this era were assembled with mineral glass crystals.