Slatkin studied at Indiana University and Los Angeles City College before attending the Juilliard School where he studied conducting under Jean Paul Morel. His conducting debut came in 1966, and in 1968, Walter Susskind named him the assistant conductor of the Saint Louis Symphony Orchestra. He stayed there until 1977, when he was made music advisor of the New Orleans Symphony.
He led a series of Beethoven festivals with the San Francisco Symphony during the late 1970s and early 1980s. These annual concerts, held during June, included the orchestra's final concert in San Francisco's War Memorial Opera House in 1980, which featured a performance of Beethoven's ninth symphony. He has continued to guest conduct in San Francisco since this time.
Slatkin returned to Saint Louis in 1979 as music director of the Saint Louis Symphony Orchestra. The national profile of the orchestra increased notably under his tenure. In 1985, he recorded the first digital stereo version of Tchaikovsky's The Nutcracker with the SLSO. (This was also the first complete Nutcracker issued on compact disc.) He remained there until 1996, and was named the SLSO's conductor laureate after his departure. His recorded work with that orchestra was represented on RCA Records, EMI and TelArc. Slatkin, a big fan of the St. Louis Cardinals baseball team, said that one of his biggest regrets in leaving the Saint Louis Symphony to become conductor of the National Symphony Orchestra would be that he would no longer be able to attend Cardinals games. He made recordings for RCA Records with the National Symphony until RCA abandoned new classical recording early in the 21st century.
He was the director of the Blossom Festival of the Cleveland Orchestra from 1990-1999. In 1996, Slatkin became music director of the National Symphony Orchestra in Washington, D.C. In 2004, it was announced that his tenure with the National Symphony will conclude in 2008. Slatkin received both praise for improving the overall quality of the orchestra and criticism for under-rehearsal of the NSO.
In 2000, he became the chief conductor of the BBC Symphony Orchestra. In 2001, he was only the second non-British person to conduct the Last Night of the Proms (Sir Charles Mackerras had been the first in 1980). This performance occurred in the wake of the 11 September 2001 terrorist attacks, and included changes to the traditional second half of the concert. He held this post until September 11, 2004, the 110th Last Night. There were reports of tension between Slatkin and the orchestra, as well as consistently negative concert reviews, which contributed to his short tenure with the BBCSO. Previously in the UK, Slatkin was principal guest conductor of the Philharmonia Orchestra from 1997 to 2000 and made a series of digital recordings for RCA with them, including the symphonies of Ralph Vaughan Williams. In 2004, the Los Angeles Philharmonic named him "Principal Guest Conductor at the Hollywood Bowl" for a two-year period; he was subsequently given a third year in the position, with his tenure ending in September 2007. In 2005, he became the principal guest conductor of the Royal Philharmonic Orchestra, London.
In 2006, he was named the music advisor to the Nashville Symphony Orchestra. In that capacity, he conducted the inaugural concert of the Schermerhorn Symphony Center on September 9, 2006. In June 2007, it was announced that Slatkin would become the Principal Guest Conductor of the Pittsburgh Symphony Orchestra beginning in 2008.
On October 7, 2007, in Detroit, Slatkin announced he had reached agreement on a three-year contract, followed by a two-year option, to become the new music director of the Detroit Symphony Orchestra, beginning with the 2008-2009 subscription season. Slatkin said he will move his family to the Detroit area and plans, eventually, to lead up to 20 of the orchestra's 26 subscription weeks.
Slatkin has conducted a wide range of repertoire, being particularly noted for his interpretations of 20th century American and British composers. His compositions, including The Raven (1971) for narrator and orchestra after Edgar Allan Poe, are little known. In addition to his earlier Saint Louis recordings for RCA and EMI, Slatkin has conducted several recordings for the Naxos label, including the first commercial recording of William Bolcom's Songs of Innocence and of Experience.