On January 21, 1989, Lake was part of Los Angeles Rams' head coach John Robinson's South team that defeated the North 13–12.
He made his professional regular season debut and first career start in the Pittsburgh Steelers' season-opening 51–0 loss to the Cleveland Browns.
[14] Head coach Chuck Noll retained Lake and Thomas Everett as the starting safety tandem in 1991, along with cornerbacks Rod Woodson and D. J.
[17] On January 21, 1992, the Pittsburgh Steelers announced the hiring of former Kansas City Chiefs' defensive coordinator Bill Cowher as their new head coach.
[18] On January 31, 1992, Cowher announced the hiring of former New Orleans Saints' secondary coach Dom Capers as their new defensive coordinator.
[21] Lake and Darren Perry returned as the starting safety duo in 1993 and played under defensive backs coach Dick LeBeau.
On September 12, 1993, Lake collected a season-high 11 combined tackles, but was carted off the field due to an injury as the Steelers lost 27–0 at the Los Angeles Rams in Week 2.
[32][33] Head coach Bill Cowher moved Lake to cornerback for the remainder of the season as a replacement for Rod Woodson, who tore his ACL in the season-opener against the Detroit Lions.
On January 28, 1996, Lake recorded five combined tackles as the Steelers lost 27–17 to the Dallas Cowboys in Super Bowl XXX.
He also received a vote for MVP from Sports Illustrated writer Peter King, which created a situation where Barry Sanders and Brett Favre tied for the award that season.
The Jaguars signed Lake to a four-year, $18 million contract which made him the highest paid safety in the league.
[40] On August 17, 2000, Lake underwent surgery on a recurring injury to his left foot and was expected to miss the entire 2000 NFL season.
Lake had undergone a surgery on his foot in March due to a stress fracture in the navicular bone near his ankle.
[44] Lake was reunited Baltimore Ravens' defensive coordinator Marvin Lewis, who was a linebackers coach with the Pittsburgh Steelers from 1992 to 1995, and former teammates Rod Woodson and Leon Searcy.
In summer 2009, Lake, along with former Steeler Greg Lloyd, was a coaching intern at the Philadelphia Eagles training camp at Lehigh University in Bethlehem, Pennsylvania.
[45] In June 2010, Lake was hired by Jerry Simon to be the assistant coach of the Marina High School boys' basketball team.
[46] He left that position as of February 7, 2018, to "return to California to be a part of his youngest son’s last year of high school football".
Lake did, however, live in the San Francisco Bay Area for three years (1979–1981) and attended Bowditch Middle School in Foster City, California.