The LEAP's basic architecture includes a scaled-down version of Safran's low-pressure turbine used on the GEnx engine.

[6] Compared to the CFM56, the LEAP makes greater use of composite materials, has a second-generation Twin Annular Pre-mixing Swirler (TAPS II) combustor, and a bypass ratio around 10–11:1.

[9][10] Reliability is also supported by use of an eductor-based oil cooling system similar to that of the GEnx, featuring coolers mounted on the inner lining of the fan duct.

According to Aviation Week's article, "The eductor device produces a venturi effect, which ensures a positive pressure to keep oil in the lower internal sump.

[1][17] The first engine entering the test program reached and sustained 33,000 lbf (150 kN) of thrust, required to satisfy the highest rating for the Airbus A321neo.

[6] CFM carried out the first test flight of a LEAP-1C in Victorville, California, with the engine mounted on the company's Boeing 747 flying testbed aircraft on 6 October 2014.

The -1C version features a thrust reverser equipped with a one-piece O-ring replacing a two-piece door.

The thrust reverser is deployed by the O-ring sliding aft, reducing the drag that was induced by the older design and improving efficiency.

[21] On 20 July 2011, American Airlines announced that it planned to purchase 100 Boeing 737 aircraft featuring the LEAP-1B engine.

[3] Also, on the A320neo, where the engine competes head-to-head with the Pratt & Whitney PW1000G, the LEAP had captured a 59% market share in July 2018.

[2] With the 737 MAX introduction, CFM delivered 257 LEAPs in the first three quarters of 2017, including 110 in the third: 49 to Airbus and 61 to Boeing, and targets 450 in the year.

[34] To cope with the demand, CFM is duplicating supply sources on 80% of parts and even subdivide assembly sites, already shared between GE and Safran.

[35] GE assembles its production in Lafayette, Indiana, US in addition to its previous Durham, North Carolina, US facility.

[35] Pratt & Whitney acknowledges a production ramp-up bottleneck on its rival PW1100G geared turbofan including a critical shortage of the unique aluminium-titanium fan blade, hitting the Airbus A320neo and the Bombardier CSeries deliveries.

[37] In mid-June 2018, deliveries remained four to five weeks behind schedule, down from six, and should catch up in the fourth quarter as the quality variation of castings and forgings improves.

Safran discovered a production quality defect on LEAP-1B low-pressure turbine disks during assembly for possibly 30 engines, and CFM is working to minimize flight-test and customer-delivery disruptions.