In 1991, in a partnership with his father, Katz paid $300,000 for the Canadian rights to the U.S.-based Medicine Shoppe drugstore franchise which had over 1,000 stores in the USA.

In 1996, Katz purchased the storied but fading Rexall drugstore chain in Canada which at the time, only consisted of several dozen stores.

The business grew and by 1998, the Katz Group consisted of 80 Rexall stores, 30 Medicine Shoppe outlets, and a few smaller independent retailers.

In 2004, Katz purchased the naming rights for ten years to the new $45-million Rexall Centre, a 12,500-seat tennis and entertainment complex on the campus of York University.

[17] Opened in September 2016, Rogers Place was marketed as one of North America's most advanced sports & entertainment venues, active year-round and featuring a 24,000 square foot grand entrance-way called the Ford Hall which can be used as public/private programmable space.

[18] With Rogers Place at its core, Katz Group has begun construction of the Edmonton Arena District (EAD),[19] slated to be Canada's largest mixed-use sports and entertainment development.

The EAD will cover 25 contiguous acres of downtown Edmonton, and feature a 50,000 square foot public plaza, two office towers, a JW Marriott Hotel, a Gateway casino, over 1,000 luxury condos and rental apartments, and 270,000 square feet of retail space at a total cost of approximately $2.5 billion.

[29] In 2019, the Oilers Entertainment Group released a statement confirming that Katz has been suffering from a life-threatening, antibiotic-resistant bacterial sinus infection.

Sportsnet hockey analyst John Shannon tweeted that Katz carried an IV bag around the clock during the Edmonton Oilers’ playoff run in 2017.

[30][31] In early 2017, Katz was accused by Brazilian actress and model Greice Santo and her husband R. J. Cipriani of offering money to the former in exchange for sexual favors.

Santo also denounced Michael Gelmon, Katz's cousin and associate, for defending him and threatening to end her career in Hollywood if she spoke about the case.

[35][36] In August 2022, the couple voluntarily withdrew their claims against Katz;[37] their lawyer issued an apology and requested that the court strike all relevant references from the record.