Zach's career in television began in the mid '80s with two appearances on Kate and Allie as the  Studio Engineer.  A very small part, but at the time, a very big deal for him.  He continued to be cast in supporting roles in various iconic '80s shows. In A Man Called Hawk, he and Wesley Snipes played two very dangerous killers, in The Equalizer, he menaced Maureen Stapleton, and in Miami Vice, he was a meddlesome emissary from the top brass. In 1988, NBC cast him in his first series regular role - Sonny Franks, the thorn in the sides of the elegant restauranteurs of Tattingers. The show was short-lived, however, and Zach returned to the theatre, with the occasional stint on Law and Order, a show in which, over twenty-some years, he played six different roles. 

In 1996, as Zach was performing in David Rabe’s A Question of Mercy at the New York Theatre Workshop, ABC cast him in C16:FBI in the series regular role of Jack Dirado, a veteran detective working in a special crimes unit under the leadership of a supervisor played by Eric Roberts. The work took Zach to Los Angeles, where, after the series' cancellation, he decided to stay, but not before a sojourn in Chicago, where he played Ivan in Yazmina Reza·s Art at the Royal George Theatre. In the ensuing years, Zach alternated among theatre, film and television roles. Appearances on many of the successful shows of the 2000s followed - shows such as The Guardian, The X-Files;· and perhaps most memorably, the first season of 24, in which he played "fixer" Carl Webb. 

In 2004, he again secured a series regular role, this time on USA Network in Touching Evil, playing boss to Jeffrey Donovan and Vera Farmiga. And again, despite critical acclaim, the show was short-lived. Months later, Zach was asked to do a role on Deadwood, one that was described to him as a one day guest star appearance in which his character Andy Cramed brought the plague to town. Having worked with David Milch on NYPD Blue, he was quick to accept. One episode led to another, and his role of Andy Cramed became more intrinsic to the plot line of the now legendary show. However, he was not a contract player, and when New York sent forth the siren song of theatre, he succumbed and spent a summer playing Dick Cheney in David Hare's Stuff Happens. After that event, it became clear that he belonged back in New York City, and that fall filmed his most compelling episode of Law and Order, Bible Story. 

By 2008, he was back on Broadway, playing Beethoven in 33 Variations. It was then that he auditioned for a new show called The Good Wife and was hired for the guest role of a lawyer in the central firm named David Lee. The character was memorable and became a integral part of the team. With the fifth season, Zach was made series regular and enjoyed playing the irrepressible Mr. Lee for the remainder of the series. 

At the end of his engagement with The Good Wife, Zach appeared in featured guest roles on Chicago PD and Blind Spot.   He also rejoined the producers of The Good Wife in the 2016 series BrainDead, playing the patriarch of a political family.

In 2018, Zach was cast in the recurring role of Ed Ferratti, incumbent mayor of NYC and candidate for re-election, in the long running series Ray Donovan. 

That same year,  Zach was cast as a series regular in Alex Garland's series for FX on Hulu, Devs. 

Zach reconjured The Good Wife's David Lee in the fourth and fifth season of Paramount+'s The Good Fight. 

Zach was first cast in a film in Claude Gagnon’s 1987 The Kid Brother, the story of a boy born with extreme physical challenges in an impoverished steel mill town near Pittsburgh.  Kenny Easterday, the kid brother of the title, played himself, and Zach had the demanding task of playing Kenny’s father in the docudrama.

After finishing that film, it was back home to Brooklyn.  A visit to the set of Mike Nichol’s Working Girl resulted in the tiny, but memorable role of Jim (dim sum anyone?).  Around the same time, Zach was cast in the Gene Wilder/Richard Pryor vehicle See No Evil, Hear No Evil, a job that saw him in a bar fight with Mr. Wilder.

A touchstone moment occurred the next year when Zach found himself working with the great Michael Caine in the film A Shock to the System.  Zach played an executive oblivious to Mr. Caine’s character’s moral descent.  Not long after, Zach worked with another legendary performer, John Candy, playing his best friend in the soap opera spoof Delirious.

Mike Figgis’s Liebestraum was next, a film noir largely set in an abandoned department store in one of the great cast iron buildings of Binghamton, NY.  Zach played the degenerate heir to the retail fortune.

One of the perks of being a film actor is the opportunity to explore different parts of the world, and Zach’s career has provided him with numerous glimpses of different countries and parts of the U.S.  In the early ‘90s, he was stationed for three weeks in Rome, working at the famous Cinecittà Studios, playing a role in Renny Harlin’s Cliffhanger, starring Sylvester Stallone.  Then it was up to Maine, for an appearance as a somewhat sinister social worker in Mel Gibson’s The Man Without a Face.

His next role brought him to Toronto, where he played Mr. Reilly, an executive in the company run by Brian Dennehy’s character and inherited by Chris Farley in Peter Segal’s Tommy Boy. To this day, he is often recognized as Mr. Reilly from this cult classic.

Around the same time, Zach found himself in Bartlett, TX, filming James Keach’s The Stars Fell on Henrietta, a film about the early days of the discovery of oil.  Zach was privileged to film his storyline opposite the masterful Robert Duvall. 

Twister was next.  Zach spent a month filming for director Jan De Bon around Ponca City and Norman, OK, during which he had the unique experience of having a plaster cast made of his head.  He also spent some time riding around with real storm chasers, but fortunately, no tornados materialized.

Then it was back to Canada, this time to Montreal, where he filmed an adaptation of Kurt Vonnegut’s Mother Night, directed by Keith Gordon and starring the wonderful Nick Nolte.  Zach had the disturbing task of portraying one of history’s most repugnant villains, Joseph Goebbels. 

More villainy ensued with Zach’s next role, that of mob boss Ivan Dzasokhov in Ringo Lam’s Maximum Risk, starring Jean-Claude Van Damme.  Fortunately, much of the film was shot in Nice, France, so Zach was able to take in the sights of that most beautiful part of the world while being hit on the head by Mr. Van Damme.

A highlight of Zach’s career was the role of Mr. Evans in Ang Lee’s Ride with the Devil.  A sensitive character study of a man facing the effects of the Civil War on the life of his family and the town in Kansas in which he lived, it was one of the more fulfilling film roles of his life, thanks in part to a superb script by James Shamus, based on Daniel Woodrell’s novel Woe to Live On.

The same year, 1999, saw Zach in a film that deals with the social changes in America in the ‘90s — David Fincher’s Fight Club.  Playing the hapless “cornflower blue tie” executive   opposite Jack, Edward Norton’s character, Zach’s look of incredulity when Jack beats himself up in front of him added a certain emphasis to the scene.

In 2006, Zach had the good fortune to work with one of his director idols, Werner Herzog, on the film Rescue Dawn, starring Christian Bale.  The role, that of a squadron commander, was small, but the chance to spend time talking with Mr. Herzog was invaluable.

The next year saw him returning to work with David Fincher on Zodiac, in which he played seasoned DOJ agent Mel Nicolai, a role in which, with the help of makeup, he played a man fifteen years his senior.

Seven years later, another opportunity to work with a great director came up when he was cast in Clint Eastwood’s J. Edgar, playing John Condon, who participated in solving the Lindbergh baby kidnapping case.

Lately, Zach completed his filming on John Keller’s Her Song, shot entirely in Antichan-de-Frontignes, a village in France’s Pyrenees Mountains.  He portrays a composer married to a novelist played by Indian film star, Kalki Koechlin.  Zach doesn’t play piano, but he learned part of a composition to play in the film.  The experience has inspired him to learn to play.

In an acting career spanning more than 35 years, Zach has been fortunate to work with some of the great film actors and directors in a medium that he reveres.  He is proud to be a character actor in the movies.