While working with Wild Dogs, Deen met and began working with Tony MacAlpine, which lead to an introduction to future long-time collaboration partner, Neal Schon. Shortly after, Neal would invite Deen to audition for a new band with Jonathan Cain, John Waite and Ricky Phillips, which became Bad English. After two albums, which included being nominated for Best New Group in 1989 at the International Rock Awards, Bad English disbanded in 1991. In 1995 a Greatest Hits was released.
Deen continued to be in various bands along with Schon, from Hardline to Paul Rodgers. After a 3-year stint with Vasco Rossi, he joined Journey, where he would spend the next 18 years and 5 albums as the lead drummer and an occasional lead vocalist. While not the original drummer for Journey, Deen has served as their drummer longer than anyone else to date and was a fan favorite.
While still with Journey, Deen, Jack Blades, and Doug Aldrich formed Revolution Saints. The band, where Deen served as lead vocalist and handled drumming duties, released its self-titled debut album in 2015 and a followup in 2017.
In late 2017 Deen became the new drummer for The Dead Daisies.