Kolek, who is 6-foot-3, was named the 2020-21 Atlantic 10 rookie of the year. He started 18 of George Mason's 21 games and averaged 10.8 points, 3.6 rebounds and 2.3 assists.
"He's about the things that go into winning," Smart said during a Zoom session with reporters. "He's about toughness. He's about work ethic. The guy's constantly in the gym. He's about making all the plays that go into winning on both ends of the floor by any means necessary."
Prosper played 22 games for Clemson and made two starts as a freshman this season. The 6-foot-8 forward averaged 2.5 points, 1.9 rebounds and 9.7 minutes.
"He can play a bunch of different positions," Smart said. "I wouldn't necessarily limit him to one spot or pigeonhole him into one spot."
Ellis, Itejere and Joplin had committed to play for Smart at Texas before following him to Marquette. Smart is taking over for Steve Wojciechowski, who was fired after going 128-95 in seven seasons.
Ellis is rated as the 31st shooting guard in his class, Joplin the 33rd-ranked power forward and Itejere the 26th-ranked center, according to ESPN's recruiting rankings.
"I appreciate the loyalty of all the guys who signed with us previously and then decided to sign with us here," Smart said. "Those guys certainly could have or would have had other opportunities, but there's a relationship there that we have."
That trio joins a freshman class that already included November signees Kam Jones (No. 162 in the 247Sports composite) and Stevie Mitchell (No. 86).
Marquette's roster is undergoing a major overhaul as the Golden Eagles begin a new era after going 13-14 this past season.
Koby McEwen and Jamal Cain - two of the Golden Eagles' top four scorers this past season - as well as Symir Torrence have announced on social media they are transferring. Cain selected Oakland, McEwen chose Weber State and Torrence picked Syracuse.
Dawson Garcia, who led Marquette in scoring (13.0) and rebounding (6.6) as a freshman, has entered his name into NBA draft consideration but hasn't ruled out a return to school.