Venable attended San Rafael High School before transferring to St. Thomas More School in Oakdale, CT. He then went on to Glendale Community College before transferring to Boise State in the spring of 2009. After transferring, Venable immediately earned a spot on the Broncos roster for the upcoming season. He would go on to start all 14 games that season. He first made an impact in an early season game against Fresno State when he recorded the first score of the game off a 30-yard interception returned for a touchdown. He is remembered by many fans for his hit on Fresno quarterback Ryan Colburn later in that same game, in which he launched himself head first, leaping over a would-be blocker, narrowly missing a sack.
2010 Fiesta Bowl
After an undefeated regular season the Broncos were matched up against fellow undefeated TCU to play in the Tostitos Fiesta Bowl. Despite being a relatively low scoring game, the final minutes became exciting after a fake punt attempt by the Broncos led to a score. With a 17–10 lead, 1:06 remaining on the clock and TCU on their own 1-yard line, the Broncos simply needed to prevent a touchdown. But TCU, led by quarterback Andy Dalton covered nearly 60 yards in under 45 seconds, setting themselves up for a potential game tying score. However, on the ensuing play Dalton threw a pass towards the left sideline which was intercepted by Venable to seal the victory.
Professional career
NFL
Chicago Bears
On July 27, 2011, following the resolution of a labor dispute between the NFL Players Association and team owners, Venable was signed by the Chicago Bears as an undrafted free agent. On September 9, 2011 Venable was fined $20,000 by the NFL for a hit he delivered on Cleveland Browns receiver Demetrius Williams in the team's final preseason game. On May 3, 2012, the Bears decided to waive him after selecting free safety Brandon Hardin in the 2012 NFL Draft. Despite his short tenure on the Bears, Venable managed to carry over the reputation as a hard-hitting defensive back he had earned in college. Said Lance Briggs when discussing the Bears lack of consistency at the safety position during the 2011 season "So between those guys, and whoever gets back there and plays, even if it's Winston Venable, I know one thing that Winston's going to do. He's going to hit somebody. So we're confident in the guys we have back there."
CFL
Montreal Alouettes
On October 3, 2012, Venable signed with the Montreal Alouettes of the Canadian Football League. In 2014, he amassed 52 defensive tackles including a career-high of nine in a game against the Ottawa REDBLACKS. Venable also recovered a league-high four fumbles and recorded 14 special teams tackles. Venable continued to be a major contributor for the Als in the following two seasons, totaling 191 tackles and 12 sacks in 35 games. Following the 2016 season Venable was not re-signed by Montreal and became a free agent on February 14, 2017.
On February 15, 2017, Venable signed with the Toronto Argonauts of the Canadian Football League as a free agent. On May 31, 2017, Venable announced his retirement.