After his first year of law school, he left to work as a head speech writer for a Democratic U.S. Senate candidate, and then for four years as a speech writer and political consultant. After political campaign work, including a position as an aide to Congressman Ron Dellums, Medved worked in advertising, and coordinated a campaign to recruit more African Americans and Hispanics to the police departments of the California cities of San Francisco, Oakland and Berkeley.
After writing more than forty articles for the book The People's Almanac, Medved wrote What Really Happened to the Class of '65?, with David Wallechinsky. Focusing on the post-graduation lives of thirty of Medved's Palisades High School classmates who were featured in a 1965 cover story in Time, the book became a bestseller in 1976. The book also became the basis for a weekly TV series on NBC that ran for 13 weeks in 1978.
Medved then wrote The Shadow Presidents: The Secret History of the Chief Executives and Their Top Aides (1979), a study of the leading White House assistants since the establishment of the presidential staff in 1857. The book included interviews with the chiefs of staff of presidents Truman, Eisenhower, Kennedy, Johnson, Nixon, and Ford. After the interviews, Medved continued his involvement in politics, becoming a friend of Ford's chief of staff, Dick Cheney, affiliating himself with the Republican Party, and campaigning for Ronald Reagan in 1980.
In 1984, Medved wrote Hospital: The Hidden Lives of a Medical Center Staff, which was discussed in Time Magazine, on ABC's Nightline, and Good Morning America. The book focused on thirty staff people who worked together in a California teaching hospital.
Medved continued to review movies, through a weekly review on CNN (1980-1983) and a show he hosted on British network Channel 4 called The Worst of Hollywood. His commentary centered on what he considered to be bad movies, particularly in "The Golden Turkey Awards". The film selected by the Medved Brothers as The Worst Film of All Time, Plan 9 from Outer Space, has since become a cult classic.
In 1984, Medved joined Sneak Previews, the weekly movie review show originated by Gene Siskel and Roger Ebert, co-hosting the program for twelve years with Jeffrey Lyons.
In 1993, Medved became chief film critic for the New York Post, a position he held for five years, during which he reviewed more than 700 movies for the newspaper.
More recently, Medved has played a prominent role in some movie-related controversies. Medved became an outspoken defender of Mel Gibson's movie, The Passion of the Christ (2004), which had been criticized as antisemitic by many prominent Jewish groups. After Mel Gibson's DUI arrest in July 2006, Medved wrote that he felt "betrayed" by Gibson's antisemitic outburst and urged Gibson to seek "reconciliation" with the Jewish community.
Some film critics, including Roger Ebert and Jim Emerson, criticized Medved for mentioning the "right to die/assisted suicide" theme in Clint Eastwood's Oscar-winning Million Dollar Baby and these critics viewed Medved's statements as a plot spoiler. Medved stated that the inclusion of this theme in the film was "deeply misleading" because it was marketed as a Rocky-esque tale of a plucky female underdog in the boxing arena. Medved said that he carefully avoided revealing the final turn in the plot, but felt honor bound to inform his listeners and readers about the movie's content and provocative point of view. Roger Ebert criticized Medved, saying he is "a political commentator and no longer a film critic.
His three hour daily show is now broadcast on 200 stations coast to coast and reaches more than 3.75 million listeners. For ten consecutive years, Medved has been listed by Talkers magazine as one of its "Heavy Hundred" most important American talk show hosts, and recently tied for eighth place in its ranking of talk hosts by audience size.
Medved describes the show as "Your Daily Dose of Debate," often focused on listeners who call in to debate issues with the host. Guests have included those who are generally considered left-of-center, including Noam Chomsky, Michael Moore, John Shelby Spong, Oliver Stone, Warren Beatty, Ralph Nader, Barbara Boxer, Al Gore, Madeleine Albright, Ben Cohen, George Galloway, and Al Franken. Guests who are generally considered right-of-center include Robert Spencer, Condoleezza Rice, and Jon Voight.
Medved describes himself as "your cultural crusader on politics and pop culture" and common themes on his show include current events, politics, American history and the entertainment industry. He reviews four or more new movies or DVD releases per week. The program also includes a monthly "Conspiracy Day," which usually occurs within a few days of the full moon due to the superstitions surrounding that event, where callers from across the country expose what they consider the "hidden forces" behind "perplexing and painful present events."
Medved writes a regular column for USA Today and is a member of that newspaper's Board of Contributors. He also writes occasional op-ed pieces for The Wall Street Journal and blogs daily at conservative website Townhall.com.
In November 2007, Medved became a senior fellow at the Discovery Institute, hub of the intelligent design movement.