"Leaving Colorado was the toughest thing I've ever done in my career - in my life, actually," Tucker told reporters, according to Yahoo Sports College Football. "But this is the right time for me to be here. The commitment is here. The resources are here. The leadership is here. Everything is here. It was the right decision."
Tucker spent last season with the Buffaloes, guiding them to a 5-7 record, including a 3-6 mark in Pac-12 play. The Spartans hired him just one week after he tweeted his commitment to building the Colorado program.
The 48-year-old explained that after Mark Dantonio retired, he didn't originally envision himself in East Lansing but believed last minute it was the right move for his career.
"Obviously there were other great candidates (for the Spartans' opening) and the search continued," Tucker said, via WXYZ Detroit's Brad Galli. "(The search) circled back to me ... and ultimately, sometime late last night, it was apparent to me that I needed to be here."
Tucker served as the defensive coordinator at Georgia for three seasons before joining Colorado in December 2018. He was also a graduate assistant at Michigan State in 1997 and 1998.
"My dream was to come back here and be the head coach," he said, per Tony Paul of the Detroit News. "That was my dream ... You can't help but aspire to be in that position one day and do that. This is certainly a dream come true to come back here."
Tucker will attempt to return the Spartans to their level of success from 2010-15 under Dantonio. After qualifying for the College Football Playoff, Michigan State went 27-24 over its last four campaigns.