Until the advent of Robert Kraft’s New England Patriots, Carroll Rosenbloom was the winningest owner in NFL history. He created a franchise that didn’t exist in Baltimore and turned it into a three-time world champion and four-time NFL champion, then made one of the savviest “trades’’ in NFL history to take over the Los Angeles Rams and continued the winning tradition he’d established after he agreed to buy the defunct Dallas Texans for $13,000 and turned them into what became Johnny Unitas’ Colts.

With the exception of Bud Adams, who helped start the AFL along with Lamar Hunt, Rosenbloom is the last of the NFL’s founding fathers not to have gained entry into the Pro Football Hall of Fame. One has to wonder why.

Carroll Rosenbloom had been a running back at the University of Pennsylvania in 1927 and 1928, where he was coached by Bert Bell. Some 20 years later, Bell would become the first powerful commissioner of the NFL and one day he would give his former player a call.

Bell has been credited with saving professional football during and after World War II and among the things he did was convince the now successful Baltimore businessman, Carroll Rosenbloom, to buy a bankrupted Dallas franchise and operate it in Baltimore.

Initially, Rosenbloom had no interest.

At 32, Rosenbloom was already retired, having transformed one of his father’s businesses, Blue Ridge Overalls, into the largest producer of denim work clothes in the country. But his days as a gentleman farmer on Maryland’s Eastern Shore ended when his father passed away unexpectedly in 1942.

Rosenbloom again took control of the company and negotiated government contracts to make uniforms and work clothes. By 1959, Blue Ridge had over 7,000 employees and Rosenbloom was called “America’s Overalls King.’’ By then he also owned the Baltimore Colts and had built them into an NFL champion after having reluctantly finally given in Bell’s insistent pleas.

In 1953, Rosenbloom put up $13,000 to buy controlling interest in what became the Colts, asking Baltimore fans to give him five years to build a champion. It took him six.

In 1958 the Colts won what is considered the most important game in league history when they defeated the New York Giants in sudden death overtime. Because the game ran late, it was still on television when fans of the Ed Sullivan show tuned in to what was then Sunday night prime time. Fans fell in love with football, the Colts and the unwanted quarterback Rosenbloom had hired several years earlier, Johnny Unitas, that evening. The explosive popularity of the NFL had begun.

During his ownership of the Colts, which ran from 1953-1971, Rosenbloom hired two future Hall of Fame coaches, Weeb Ewbank and Don Shula, signed Unitas in 1956 and built a team that won the NFL championship in 1958, 1959, 1968 and 1970 while losing Super Bowl III to the New York Jets in the second most important game in NFL history and winning Super Bowl V.

In 1960, it was Rosenbloom who suggested league owners consider little known Rams’ general manager Pete Rozelle as a compromise candidate for commissioner after 23 ballots had been taken without breaking the deadlock over who would replace Bell after his death of a heart attack in the stands at an Eagles’ game the previous October.

Rozelle was only 33 and a former P.R. man but Rosenbloom had seen the job Rozelle did making the Rams’ profitable despite warring ownership factions after he took over as general manager and was impressed both with his business savvy and negotiating ability.

Rosenbloom supported Rozelle’s plan to have equal sharing of all television revenue and a national contract rather than individual ones that existed at the time before revenue sharing leveled the competitive playing field. It was a stroke of brilliance that directly led to the exploding profitability of once struggling NFL franchises. Although it was Rozelle’s idea, without the support of the powerful Rosenbloom it is unlikely it would have been adopted.

Rosenbloom also played a pivotal role in the NFL-AFL merger in 1970, agreeing to allow the Colts to be moved into the newly formed AFC along with the Pittsburgh Steelers and Cleveland Browns. While the other two went as a gesture of solidarity after most NFL owners refused, Rosenbloom forced the AFL’s owner to pay him $3 million to do it. Carroll Rosenbloom was always a master of leverage.

He was one of the negotiators of the league’s first big national TV contracts and typical of the sly way he often operated, he used his inside information of those negotiations to buy out his partners before the deals were complete. Rosenbloom realized the bonanza each team was about to receive and knew he would be quickly able to recoup what he’d paid to buy them out.

It was also Rosenbloom who first realized stadiums could be used to generate revenue with luxury suites. When he could not get the cooperation he sought from Baltimore politicians for renovations of Memorial Stadium or to have a stadium built solely for the Colts, he pulled off a brilliant business move following the 1972 season.

Rosenbloom negotiated a tax-free trade with Robert Irsay, who had just purchased the Los Angeles Rams for $19 million from the estate of Dan Reeves. The swap gave him the Rams while Irsay took over the Colts but because the swap did not involve cash, Rosenbloom avoided $4.4 million in capital gains taxes and soon after owed a franchise worth $25 million.

The Colts had become one of the dominant teams in the league under Rosenbloom but after he left they did not win a playoff game for 23 years.

Meanwhile, Rosenbloom built another winning franchise in Los Angeles. Although the Rams did not win a Super Bowl they were a consistent playoff team and reached the Super Bowl in 1979, eight months after he drowned under mysterious circumstances.

Although his death was declared a result of a heart attack while swimming there were many who believed foul play had been involved. Well known as a gambler and alleged to have wagered on his own team often enough that Rozelle launched a six-month investigation into those claims before declaring Rosenbloom clear of the charge, Rosenbloom’s death remained an unsolved mystery to some, including his son, Stephen.

Carroll Rosenbloom was a towering figure in the NFL between 1951 and 1979. He built two franchises into consistent winners, one from the ashes of a failed franchise in Dallas. At the time of his death, no owner had ever been as consistently successful both financially and on the field.

Rosenbloom’s teams went 226-116-8, a winning percentage of .660 which was the best in history until Kraft’s 24 years of ownership of the Patriots left him with a .696 winning percentage. The Patriots have won five Super Bowls and are 5-4 in Super Bowl games. Rosenbloom’s Colts and Rams won three NFL championships (1958 and 1959 came in pre-Super Bowl days) and were 3-2 in championship games (1-2 in Super Bowls).

Many have argued that the first test for a Hall of Fame candidate is to ask the question, “Can you write the history of the NFL without him.’’ If one accepts that as a reasonable measuring stick, Carroll Rosenbloom measures up. Between creating the Colts, forcing the hiring of Rozelle, swapping franchises to take over the Rams and envisioning the use of stadiums as major revenue drivers, Carroll Rosenbloom left an impact on the NFL like few other owners.

“Carroll Rosenbloom played a major role in the growth and success of the NFL, both through the teams he produced and through his active participation in the league’s decision-making process,’’ Rozelle said at the time of Rosenbloom’s death. He should know. Pete Rozelle was in the middle of those decisions as the most powerful and successful commissioner in sports history because Carroll Rosenbloom put him there.