John J. McMullen, Ph.D (May 10, 1918 – September 16, 2005) was an American naval architect, businessman, and marine engineer, and former owner of the New Jersey Devils and Houston Astros.

He founded the engineering firm John J. McMullen & Associates, and was the owner of Norton Lilly International[1] a shipping agent now based out of Mobile, Alabama, from 1972 until 2002.

Under McMullen's ownership, the Astros signed Alvin, Texas native Nolan Ryan to baseball's first $1 million free agent contract and reached the playoffs for the first time in franchise history in 1980.

On July 24, 1992, it was announced that McMullen had come to an agreement with Drayton McLane to sell the team, which also included the lease on the Astrodome for a total of $117 million; approval by the league owners followed in the fall.

[18][19][20] It was during this season that the Astros were to play 26 consecutive road games from July 27 through August 23, due to the 1992 Republican National Convention being held at the Astrodome from August 17–20 (since the RNC required a couple of weeks to prepare the staging), as agreed on by McMullen without getting approval from the Players Association.

McMullen was behind the acquisition of players that would play a part in the Astros resurgence in the late 1990s, such as draft picks Craig Biggio and trade prospect Jeff Bagwell.

McMullen went through four general managers during this time from Tal Smith (1979–1980), Al Rosen (1980–1985), Dick Wagner (1985–1987), and Bill Wood (hired in 1987); he went through four different managers: Bill Virdon (fired in 1982), Bob Lillis (1982–1985), Hal Lanier (1986–1988), and Art Howe (hired in 1989, fired by McLane in 1993).

McMullen was involved in the purchase of one further professional team with the Colorado Rockies of the National Hockey League.

The Rockies were intended to move out of Colorado before McMullen bought the team, but a flurry of sales complicated things.

They had a verbal agreement, but Gilbert listened to a meeting with George Steinbrenner before going back to McMullen, with a formal purchase occurring on May 28 that allowed the team to move to New Jersey.