Robbert was born in the Bronx but lived on the Upper Westside and Kew Gardens, Queens before returning back to the Bronx at the age of 11. He was first exposed to basketball as a member of City Mission Society's Cadet Corps where he learn the fundamentals of the game from the Honorable William (Billy) E. Clarke. He became a member of the Pen & Scroll Military Fraternity. Robbert attended and graduated from Manhattan Vocation Technical High School, where he was a four year member of the senior varsity basketball team. He earned the nickname Rob Silk (he would say because of his smooth jump shot, others might say because no one could pronounce his last name).
After completing high school, he enrolled at SUNY's Fashion Institute of Technology where he played one year as a member of the Tigers. After one year of college basketball, he decided to enlist into the US Air Force where he earned an Associates Degree in Business Administration from the Community College of the Air Force. He also achieved the rank of Sergeant and was awarded a Meritorious Service medal for his part in Operation of El Dorado Canyon in 1986. While serving in the military, he attended night classes at Syracuse University, where he earned his BA in Business Management. Robbert was also a member of the Orange's practice squad where he was awarded two rings: 1987 Final Four Championship and 1988 Big East Championship.
In 1994 he took a job at the NBA league office working in Basketball Operations as a Technical Manager. He helped create the first version of the www.nba.com website. He taught computer skills to league officials and players alike. He worked with Bob Lanier supporting his Team Up campaign and conducted NBA sponsored Stay In School basketball camps all around the world. He was also a technical advisor at the NBA's 1997, 1998 and 1999 Rookie Transition Programs. Robbert played in several NBA sponsored Pro Summer League tournaments. He parted ways with the NBA in 2000 to pursue other career goals.
Robbert is dedicated to teaching younger players the importance of discipline, practice, teamwork and fair play on and off the court and especially in the classroom.