A native of Corning, New York, Tillman served in the United States Navy as a fleet support officer.

[6] Tillman then moved to the United States Naval Academy, where he served as an assistant and formulated the offensive game plans for the Midshipmen.

[6] In 2002, he was promoted to the position of Head Assistant Coach, and from 2004 to 2007, Navy was one of just five NCAA teams to qualify for the tournament each season.

On June 15, 2010, Inside Lacrosse and The Baltimore Sun reported that the University of Maryland had hired Tillman to replace former head coach Dave Cottle.

He discussed his players and their personalities with former coach Dave Cottle, whom he invited to address the team after the regular season in which they lost to four underdog opponents.

[13] Tillman also consulted with Hall of Fame inductee Dick Edell, who led Maryland to three finishes as national runners-up.

"[14] After the season, Navy expressed interest in hiring Tillman as replacement for retired head coach Richie Meade, but he elected to remain at Maryland.