Beatrice was born in July 1943. His family was Italian-American. He graduated from Boston College with a degree in geology. He initially wanted to be a meteorologist, but instead decided to channel his passion for sports into broadcasting.
In 1975, Beatrice joined WBZ radio as the weekend host of Calling All Sports. He replaced Guy Mainella as weekday host in 1976, but was moved back to weekends after five weeks and succeeded by Bob Lobel.
In 1977, Beatrice joined WMAL as host of Sports Call, the station's nightly sports show, and the Washington Redskins pregame show. He became one of the city's most prominent and highest rated radio hosts. On February 20, 1981, Beatrice admitted to the The Washington Star that he had made "exaggerations" about his accomplishments on the air. He confessed that he did not football at Boston College, that his doctorate degree was from a diploma mill in Ohio, and that his scouting system only involved people who scouted as a hobby. His admission came as The Washington Post was about to publish a story by Tony Kornheiser written after several weeks of intense questioning in which Beatrice admitted that he had no role in the Boston Patriots drafting Fran Tarkenton. He took a leave of absence after the story broke, but returned after five weeks. On August 16, 1991, Beatrice suffered a heart attack, which required him to undergo triple bypass surgery and miss many weeks of work.
By 1995, Beatrice's ratings had decreased to 5,000 listeners per fifteen minutes (down from 20,000 in 1990). On October 4, 1995 it was announced that WMAL was dropping Beatrice's show. The station's decision resulted in 200 phone calls and about 40 letters from supporters. His final program aired on October 6 and featured calls from Washington Redskins head coach Norv Turner, Redskins general manager Charley Casserly, and Washington Bullets head coach Jim Lynam.
On October 16, 1995, Beatrice signed a contract to host a sports program on a radio network owned by Sam Huff. The program originated from Middleburg, Virginia, but was syndicated nationally, including on WTEM in Washington D.C. On April 20, 2000, Beatrice retired from radio.
Beatrice was known for his high-pitched voice, pronounced Boston accent, encyclopedic knowledge of sports (especially NFL Draft prospects), opinionated nature, respectful treatment of kids who called into his show, and his long running promos for Arby's. He also had a tendency to talk over guests and callers, repeat the same points over and over again, go off on tangents, and lecture guests. His catchphrase was "You're next!"
- Crowe, Gretchen R. (May 18, 2011). "'You're next' at the lectern". Catholic Herald. Retrieved January 18, 2015.
- Craig, Jack (November 21, 1976). "Ken Beatrice: All the facts". The Boston Globe.
- Craig, Jack (March 1, 1981). "Press silences Beatrice". The Boston Globe.
- Shapiro, Leonard (September 13, 1991). "Beatrice Banks His Broadcasting Fires After Getting a Warning: 'You're Next'". The Washington Post.
- Denlinger, Ken (October 7, 1995). "Callers Say Goooodbye To WMAL's Beatrice". The Washington Post.
- Shapiro, Leonard (October 17, 1995). "Beatrice's Show Will Go On". The Washington Post.
- Shapiro, Leonard (April 18, 2000). "WTEM Talk Show Host Beatrice to Retire". The Washington Post.
- Shapiro, Leonard (June 2, 2010). "Top 10: Dialing up the best in Washington sports radio". The Washington Post. Retrieved January 18, 2015.
- Bloomquist, Randall (February 17, 1986). "You're Next! Loving and Hating Beatrice on WMAL". The Business Review.
- Nakamura, David (April 21, 2000). "Ken Beatrice's Sweet Talk; A Fond Farewell to The 'Sports Call' Host". The Washington Post.