Wisniewski was drafted in the second round (#29 overall) of the 1989 NFL Draft by the Dallas Cowboys. He was then immediately traded to the Raiders, where he would play all of his 13 seasons in the league. "Wiz" became the standout Guard of the 1990s and made the Pro Bowl 8 times in his career tying him at the time of his retirement with Art Shell, Howie Long, and Tim Brown (Who would later surpass him) for most by a Raider. He was also named to the NFL 1990s All-Decade Team and was a first team All-Pro twice.
On January 27, 2011 it was announced that Wisniewski would be returning to the Oakland Raiders as an assistant offensive line coach under new Head Coach Hue Jackson, new offensive coordinator Al Saunders and new offensive line coach Bob Wylie. He was thrilled by saying "I'm back to my first love, the Oakland Raiders and working with the Offensive Line. I’m a Raider for life. I can help in technique, help in mindset and attitude and really push these young men to develop and to be the heartbeat of the team." Wisniewski said via the Raiders website. He also said in a statement that "I’m thrilled to be working in the building again for the Silver and Black and helping to shape the future of the offensive line." He and Wylie replaced Chris Morgan and Jim Michalczik, who were not retained for the 2011 season.
Following the death of Raiders owner Al Davis in October 2011, Jackson's firing the following January and the hirings of new general manager Reggie McKenzie and new head coach Dennis Allen, Wisniewski, one of the few coaches retained by the new regime, was slated to assist under new offensive line coach Frank Pollack. However, right before the start of training camp in July 2012, it was announced that Wisniewski had resigned for "personal reasons" but would remain with the club as an ambassador.
Wisniewski lives in Oakland, California and maintains an association with the Raiders. He spent one year at Stanford University, helping coach the offensive line on a team that reached the Orange Bowl Wisniewski is a born-again Christian  and currently volunteers at The Well Christian Community Church in Dublin, California, the church founded by fellow ex-Raider, Napoleon Kaufman.
His brother, Leo, was a three-time letterman for the Penn State football team (1979–1981). Wisniewski's nephew (Leo's son), Stefen, was a guard/center on the Penn State team. Stefen had a standout career with Penn State, was drafted by the Oakland Raiders with the 48th pick in the 2011 NFL Draft, and is currently the Raiders' starting center.