Schmitt grew up in New York City. After serving in the U.S. Navy, he began working at Apex Recording Studios at the age of 19. In the late 1950s Schmitt moved to Los Angeles and became a staff engineer at Radio Recorders on Santa Monica Blvd in Hollywood. In the early 1960s he moved to RCA in Hollywood as a staff engineer. While at RCA he engineered albums for Henry Mancini, Cal Tjader, Al Hirt, Rosemary Clooney, Liverpool Five, The Astronauts, Sam Cooke ("Bring It On Home to Me," "Cupid," "Another Saturday Night") in 1961. He also did a lot of motion picture scoring work for Alex North and Elmer Bernstein. In addition, Schmitt worked with Jascha Heifetz's "Million Dollar Trio", which comprised Heifetz himself, Arthur Rubinstein on the piano, and Gregor Piatigorsky or Emanuel Feuermann on cello. Schmitt once stated that "Mr. Heifetz was very temperamental in the Studio." He has also stated that Heifetz would have angry fits during recording sessions.
In 1966 Schmitt left RCA and became an independent producer. He produced albums for Jefferson Airplane, Eddie Fisher, Glenn Yarborough, Jackson Browne and Neil Young. In the mid 1970s he began spending more time engineering again, recording and mixing artists from Willy DeVille to Dr. John.
Other career highlights include engineering both Frank Sinatra Duets albums, Ray Charles' Genius Loves Company and some of Diana Krall's albums. Much of his work in the last few years has been with producer Tommy LiPuma. He has also recorded Sammy Davis, Jr., Natalie Cole, Thelonious Monk, Elvis Presley, Tony Bennett, Madonna, Michael Jackson, and many others.
Most recently, in 2014, Schmitt worked on Bob Dylan's album, Shadows in the Night, which was released on January 30, 2015.
Since he moved to Hollywood, Schmitt has almost exclusively worked at Capitol Studios, with occasional sessions at United Recording Studios and EastWest Studios, formerly Western Recording. He made an advertisement for AMS Neve's 88R console at Capitol's Studio A, which currently holds an 88R.
Schmitt has also appeared on the online internet television series "Pensado's Place", hosted by Dave Pensado and Herb Trawick. During one of the segments he mentioned that his favorite microphone is the Neumann U 67 tube (valve) condenser microphone, and explained that he uses the microphone on numerous sources.Jazz Suite on the Mass Texts – Paul Horn, composed and conducted by Lalo Schifrin (RCA Victor, 1965)
After Bathing at Baxter's – Jefferson Airplane (1967)
Crown of Creation – Jefferson Airplane (1968)
Bless Its Pointed Little Head – Jefferson Airplane (1969)
Volunteers – Jefferson Airplane (1969)
Hot Tuna – Hot Tuna (1970)
Late for the Sky – Jackson Browne (1974)
On the Beach – Neil Young (1974)
We Got By – Al Jarreau (1975)
Farther Along – Spirit (1976)
Glow – Al Jarreau (1976)
Look to the Rainbow – Al Jarreau (1977) (co–produced w/Tommy LiPuma)
All Fly Home – Al Jarreau (1978)
Dream Machine – Paul Horn (1978)
During his career, Schmitt has recorded and mixed more than 150 gold and platinum albums.
He has won more Grammy Awards, more than any other engineer or mixer. He was the first person to win both the Grammy and Latin Grammy for Album of the Year. He won his first Grammy in 1963 for engineering the Hatari! soundtrack by Henry Mancini. The song "Moon River" and its associated album won two Grammy awards in 1961 as well as an Academy Award for Best Song with its appearance in the film Breakfast at Tiffany's. He was awarded two Latin Grammy Awards in 2000 including Album of the Year. In 2005 he won five Grammys for his work on Ray Charles' Genius Loves Company, including Album of the Year, setting the record for most Grammys won by an engineer or mixer in one night. In 2006, he was given the Grammy Trustees Lifetime Achievement Award.
In 2014, Schmitt was awarded a star on the Hollywood Walk of Fame. The star recognizes his contribution to the music industry and is located at 1750 N. Vine Street.
Don Was, Joe Walsh, and President/CEO of the Hollywood Chamber of Commerce, Leron Gubler were speakers at Schmitt's Star Unveiling Ceremony. Gubler declared that August 13 would be designated 'Al Schmitt Day' in Hollywood. Although Natalie Cole and Paul McCartney were unable to attend the ceremony, both released statements that were read by Gubler at the ceremony.
He was inducted into the TEC Awards Hall of Fame in 1997.
In June 2014, he won the Pensado Giant Award. In September 2014, he received an honorary doctorate from the Berklee College of Music.