The 30-year-old moves to The City Ground from Greek side Olympiacos.
Guerrero has experience of playing in the Champions League and Europa League, scoring six times in 20 outings, while also featuring over 80 times in La Liga.
The frontman began his career in the youth ranks of Atletico Madrid and Real Madrid but made his senior debut with Albacete B. He then moved to Sporting Gijon.
He switched to La Liga outfit Leganes in 2016, helping them preserve their status in the Spanish top flight ahead of joining Olympiacos in 2018. Miguel has competed 89 times in the Spanish top flight.