The aircraft family was launched with the Legacy 500 in April 2008 and were the first jets in the size category to feature a flat-floor stand-up cabin and fly-by-wire.

The Legacy 500, with a range of 3,125 nautical miles [nmi] (5,790 km; 3,600 mi) and room for up to 12 passengers, first flew on November 27, 2012, and was certified on August 12, 2014.

The shorter Legacy 450 first flew on December 28, 2013, was certified on August 11, 2015, has a range of 2,900 nmi (5,370 km; 3,340 mi), and can accommodate up to 9.

At the August 2007 National Business Aviation Association convention, Embraer unveiled a cabin mock-up of two concepts positioned between the $7 million Phenom 300 and the $26 million Legacy 600, called midsize jet (MSJ) and mid-light jet (MLJ), positioned on 22% of the market in units.

Honeywell HTF7500E turbofans were selected along a Rockwell Collins Pro Line Fusion avionics suite integrated cockpit and a Parker Hannifin fly-by-wire flight control system.

[6] The first Legacy 450 produced in Florida was delivered in December 2016; the fuselage is built in Botucatu in Brazil, and the wings in Évora, Portugal.

Active load alleviation deflects both ailerons upward at 2.0 Gs to prevent overstressing the wing without adding structural weight.

[22] On 23 December, the first was delivered to fractional operator Flexjet, two months after signing for 64 jets, including Praetor 500/600s and light Phenom 300Es.

[24] They are low wing, T-tail airplanes with cabin pressurization, powered by two rear mounted turbofans.

[25] Embraer offers an enhanced flight vision system constituted by the Rockwell Collins HGS-3500 Head-up display combined with the EVS-3000 Infrared camera, permitting a decision altitude necessitating visual references of 100 ft above touchdown at a projected price of $515,000.

Federal Aviation Administration's draft AC 20-167A further proposes a descent below 100 ft if the required visual references can be observed using the EFVS, similar to Cat II and III approaches with limited instrument landing systems in many small airports.

[26] Embraer's timeline was delayed because software development for the fly-by-wire flight control system was running behind schedule.

[27] Supported by 800 engineers, the first Legacy 500 prototype (PT-ZEX) was rolled out on 23 December 2011 to begin ground testing and systems evaluation, prior to the aircraft’s first flight scheduled for the third quarter of 2012.

[48] Embraer announced on 22 December 2015 its first delivery to LMG, LLC, an American provider of video, audio, and lighting support headquartered in Orlando.

Dispatch reliability often exceeds 99% with most components mounted outside the pressure vessel for easy access if it breaks, except batteries and potable water servicing.