(written from a Production point of view)
Smitrovich is perhaps best remembered for his portrayal of Drew Thatcher on the family drama series Life Goes On. Smitrovich starred in this series for all of its four seasons (1989-93). Prior to this, he was a regular on the NBC series Crime Story, where he played Detective Danny Krychek.
Four years after Life Goes On, Smitrovich had a recurring role as Bob "Bletch" Bletcher in Chris Carter's Millennium series, on which Terry O'Quinn was a regular. Smitrovich had previously co-starred with O'Quinn in the films Without a Trace (1983, in which both Smitrovich and Thomas Kopache appeared as policemen), Silver Bullet (1985, with Leon Russom and Lawrence Tierney), and Ghosts of Mississippi (1996, co-starring Whoopi Goldberg, Susanna Thompson, Brock Peters, Richard Riehle, and Bill Cobbs).
Smitrovich's early film credits also include the 1984 comedy Splash (with Clint Howard, Charles Macaulay, Jill Jacobson, Christopher Thomas, Valerie Wildman, and Patrick Cronin), Michael Mann's 1986 thriller Manhunter, and the 1989 crime drama Renegades (co-starring Robert Knepper), and the 1989 film Her Alibi (with William Daniels). He later starred in such films as the 1996 science fiction blockbuster Independence Day (with Brent Spiner, Erick Avari, Leland Orser, Raphael Sbarge, Robert Pine, and Tim Kelleher), 1996's The Phantom (with Leon Russom and Cary-Hiroyuki Tagawa) and The Trigger Effect (with Rick Worthy and William Lucking), 1997's Air Force One (with Dean Stockwell), and the 2000 political thriller Thirteen Days (with Steven Culp, Tim Kelleher, and Kevin Conway).
Additionally, Smitrovich made two guest appearances on Miami Vice, one in 1984 and another in 1985. His "Past Tense" co-star Frank Military (Biddle Coleridge) was a writer for that series. Smitrovich later made guest appearances on such television shows as Murder, She Wrote (with Gregory Itzin), NYPD Blue (starring Gordon Clapp and Sharon Lawrence), the 1998 remake of Fantasy Island (starring Mädchen Amick and Malcolm McDowell, in an episode with Louise Fletcher), 24 (with Roger R. Cross), The Nine (starring John Billingsley), Eli Stone (with Ethan Phillips), and Desperate Housewives (starring Teri Hatcher).
From 2001 through 2003, Smitrovich had a recurring role as Assistant District Attorney Kenneth Welsh on the TV drama The Practice. He also made two additional appearances as Walsh in 2004. During his time on this show, Smitrovich worked with such Star Trek performers as Earl Boen, Ellen Bry, Alan Dale, Eve Brenner, Richard Cox, Bari Hochwald, Clyde Kusatsu, John Larroquette, Virginia Madsen, Mark Margolis, Dakin Matthews, Carolyn McCormick, Richard McGonagle, Mark Moses, Alan Oppenheimer, Andrew Robinson, Cristine Rose, Jennifer Savidge, Mark L. Taylor, and Star Trek: The Original Series star William Shatner.
During his time on The Practice, Smitrovich was also starring as Inspector Cramer on the A&E series A Nero Wolfe Mystery (with Saul Rubinek), which ran for 29 episodes from 2001 through 2002. He also had roles in the made-for-TV films Fail Safe (2001), in which he co-starred with James Cromwell, and The Reagans (2003), in which he played the role of Alexander Haig.
More recently, Smitrovich co-starred with Patrick Stewart in the 2005 film The Game of Their Lives and had a supporting role in Paramount Pictures and Marvel Studios' blockbuster Iron Man (with Faran Tahir). His upcoming films include Flash of Genius and Seven Pounds, both co-starring Tim Kelleher.
Since 2004, Smitrovich has recurred as Special Agent Alexander Olczyk on Without a Trace, the CBS crime drama starring Enrique Murciano. Other Star Trek actors he has worked with on this show include John Cothran, Jr., John Doman, Claudette Nevins, and Jennifer Parsons.
As a Screen Actors Guild (now SAG-AFTRA) member, Smitrovich worked in several positions for this union and was recently voted to serve as SAG National Board alternate and to the Hollywood Division Board of Directors. 
Between 2017 and 2018, Smitrovich appeared as Tom Carrington in three episodes of the Dynasty reboot where he worked alongside Alan Dale.