The 30-year-old Englishman adds bags of experience to the Reds attacking options, counting a number of Football League and National League teams as his previous employers.
Most recently Morgan-Smith was with AFC Telford United and joins forwards Ben Tomlinson and Dec Bacon in the reds attacking options.
“Amari joins us with a wealth of experience after being at Telford last season and York before that," Alfreton boss Billy Heath told the club's official website. "He brings strength and power to us and a real eye for goal."
Heath also admitted Morgan-Smith was someone he's been keen on for some time.
“He can play as a target man and also down the sides. We are delighted to have him here, he’s been a player that’s been on my radar for a while and it’s a great acquisition to the squad.”
Alfreton Town get their 2019/20 National League North season underway against Brackley Town on August 3.