The Legacy 450 and 500 were introduced at the 2007 NBAA convention as a concept called mid-size jet (MSJ) and mid-light jet (MLJ).
Both aircraft are powered by two Honeywell HTF7500E turbofans. Both come equipped with a Rockwell Collins Pro Line Fusion avionics suite. These aircraft were renamed the Legacy 500 and the Legacy 450. These aircraft have 95% systems commonality.
The Legacy 450 first flight occurred on 28 December 2013. It received its Brazilian certification on 11 August 2015 and was certified by the FAA shortly after on 31 August 2015.
The Legacy 450 fuselage is four feet shorter than the Legacy 500.