Liscio was selected by the Green Bay Packers in the third round of the 1963 NFL Draft. He was also drafted by the New York Jets in the tenth round of the 1963 AFL Draft. He signed with the Packers, and during training camp he was used as a defensive end and defensive tackle. He was eventually released the week of the season opener on September 10.
Liscio was claimed off waivers by the Dallas Cowboys, who switched him to offense, and named him the starter at left tackle at the end of his rookie season. He became a stalwart on the Cowboys offensive line for almost a decade and was only the second player in franchise history to hold this position after replacing Bob Fry. In 1964, Liscio started 10 games before being placed on the injured reserve list with a right knee injury. He lost all of the 1965 season after suffering complications from an offseason knee surgery. In 1966, he recovered enough to resume his career, was named starting left guard, and eventually moved back to left tackle at the end of the season. The next year, he played in the 1967 NFL Championship Game, famously known as the "Ice Bowl". In 1970, he played in only 11 games because of back problems. During his first eight seasons, Liscio helped Dallas reach two NFC Championships and one Super Bowl, while playing in 89 games, many of them with injuries. On May 19, 1971, he was sent to the San Diego Chargers as part of the “Bambi” trade that brought Hall of FamerLance Alworth to the Cowboys.
San Diego Chargers
Liscio never played a game for the Chargers because of injuries. He had problems with both of his hamstrings and a flare up the back problems that cost him the second half of the 1970 season. On September 8, 1971, he was traded to the Miami Dolphins along with a fourth round draft choice in exchange for center Carl Mauck.
Miami Dolphins
Liscio never played a game for the Miami Dolphins either, because he announced his retirement after the trade became official, rather than reporting to the team.
Dallas Cowboys (second stint)
In mid-November 1971, the Cowboys needed help at left tackle after multiple injuries at the position hit the team. Ralph Neely fractured his leg in a motorcycle accident, Don Talbert broke a bone in his foot, and Forrest Gregg was limited in the last season of his 16-year Hall of Fame career. Tom Landry called Liscio on Monday November 15, and he reported to the team on Wednesday to start at left tackle against the Washington Redskins on Sunday. Liscio played his first game back with his right leg taped from the ankle to the hip and both shoulders hurt. The Cowboys won 13-0, earning first place in the NFC East division. His opponent that day was defensive end Verlon Biggs, who never reached the quarterback. He did not allow a sack in the eight starts during his comeback and the team was undefeated with him at left tackle. He and Alworth were also Super Bowl VI teammates. In that game, Liscio successfully blocked Bill Stanfill, helping Duane Thomas and other running backs register 252 rushing yards. Liscio retired after being the runner-up for the NFL Comeback Player of the Year Award.
Personal life
After football, he worked in commercial real estate. In 2012, he suffered a heart attack while being present at the Dallas Cowboys training camp. Liscio died on June 18, 2017, at age 76 at his Lake Highlands home. He was diagnosed with amyotrophic lateral sclerosis after falling and breaking his hip in mid-2016 and began slurring his words. He had lost his ability to speak and required a feeding tube, according to his wife, Annette, to whom he was married since 1963. She believed playing football had contributed to his condition and, upon his death, donated his brain to be tested for chronic traumatic encephalopathy. He was survived by her and their three children.
