Rosenblatt led his hometown with warmth and optimism; one of six children born to Jewish immigrant parents, he started selling newspapers at age seven.

As a semipro player, under the name Johnny Ross, Rosenblatt faced Satchel Paige, the famed Negro league pitcher.

After starring as an athlete at Tech High in Midtown Omaha, Rosenblatt attended the University of Iowa on a baseball scholarship but had to leave college to help support his family.

The young Rosenblatt played baseball in sandlot leagues for a few years, then Roberts Dairy came calling for the left-handed outfielder in 1933.

The idea for building a ballpark received major impetus in 1944 when Omaha was ruled out as a possible site for an American Association franchise because it lacked a suitable stadium.

The inaugural event in October 1948 drew some 15,000 fans, who saw major leaguers and Nebraska natives Rex Barney, Richie Ashburn, and Johnny Hoop compete against a collection of sandlot and minor league players.

He did pull off a Los Angeles Rams–New York Giants exhibition football game that attracted 13,000 fans and generated $9,000 for Children's Hospital.

He joined Ed Pettis and Morris Jacobs in persuading the NCAA to relocate championship baseball series to Omaha's new stadium.

In June 1961, just after James Dworak had assumed the mayor's office, Rosenblatt received a lifetime pass to the stadium he built.

Ironically, as head of the Chamber of Commerce Sports Committee in 1963, Rosenblatt appointed a subcommittee to review the possibility of a downtown stadium.

His son, Steve, served on the Omaha City Council from 1973 to 1981 and as a Douglas County commissioner from 1981 to 1995, and later relocated to Phoenix, Arizona.