He began his career at age six, appearing in television commercials, including the popular “Betcha bite a chip” campaign for Chips Ahoy!. In 1990, he landed his first film role, as Chickie in Rocky V. Two years later, Connolly was cast as Shaun Kelly in the film adaptation of Myron Levoy’s novel Alan & Naomi, and co-starred with Tobey Maguire in the short-lived Fox sitcom Great Scott!. His appearance in the series later earned him a Young Artist Award nomination for Best Young Actor Co-starring in a Television Series. He portrayed Dabney Coleman‘s son in the comedy film The Beverly Hillbillies. Connolly continued guest starring in television series including Wings, Getting By and the medical drama ER.
From 1995–96, Connolly starred in Don’s Plum alongside future collaborators Tobey Maguire and Leonardo DiCaprio. Later that year, he landed the role of Ryan Malloy on the situation comedy Unhappily Ever After. The series also marked Connolly’s directorial debut when he directed six episodes in its fourth season. In 2007, Connolly made his full-length movie directorial debut with the film Gardener of Eden, which premiered in April 2007 at the Tribeca Film Festival.
Connolly’s best-known role is the character Eric Murphy, better known as “E”, on HBO‘s show Entourage. E is the manager and best friend of Vincent Chase, who is played by Adrian Grenier. In 2009, Connolly received a nomination for Golden Globe Award for Best Performance by an Actor in a Television Series – Musical or Comedy, and in September 2011 the show ended with its eighth season. In 2015, Connolly reprised his role as Eric in the Entourage film adaptation.
In addition to television work, Connolly has appeared in several major motion pictures including Antwone Fisher, Secretariat, John Q and The Notebook. In August 2007, he signed on to play a supporting character in He’s Just Not That Into You, which was released in 2009.
Connolly attended the 2010 NHL Entry Draft in Los Angeles and announced the final pick of the first round for the New York Islanders. He also directed the documentary film Big Shot, which screened at the 2013 TriBeCa Film Festival and the 2013 Hamptons International Film Festival. The film revisits the fraud perpetrated by would-be Islanders owner John Spano in 1996.
In September 2015, it was announced that Connolly would direct The Life and Death of John Gotti, a film about infamous mobster John Gotti and his son, John A. Gotti, who succeeded him. Academy Award-nominee, John Travolta is set to play the former.