Started playing trumpet when he was nine years old with his father, Boyd McNab, as his first teacher.

The young McNab won a PTA scholarship which allowed him to take trumpet lessons from Walter Laursen, noted Pasadena teacher and musician. Laursen made it possible for McNab to play trumpet in the Pasadena Symphony at age 16.
Malcolm started studying at the age of 19 with James Stamp, a relationship that continued thereafter for many years. After touring with the San Francisco Ballet and an army stint with the West Point Band, he studied privately with William Vacchiano and John Ware, both of the New York Philharmonic Orchestra. He then toured the state of Maine for a year with a brass quintet. Returning to the Los Angeles area in 1969, McNab began his successful career as a studio musician and performer with symphony, ballet and theater orchestras.
Solo appearances include the California Chamber Symphony, Denver Symphony, Los Angeles Pops, Hollywood Bowl, San Diego Symphony, Long Beach Symphony, and the Pasadena Pops. Two-time winner of the Most Valuable Player Award of the National Academy of Recording Arts and Sciences, McNab has appeared on numerous records with major recording artists from 1970 to the present. These include concert groups such as the L.A. Philharmonic Orchestra, L.A. Chamber Orchestra, N.Y. City Opera; popular artists such as Dionne Warwick, Frank Zappa, Peggy Lee, Chicago, Singers Unlimited, and The Carpenters. He can be heard on the Olympic recordings of 1984,1988,and 1992.
His television experience includes playing in the Academy Awards, Grammy, and Emmy Awards orchestras for many years;performing on the title tracks of the major network news themes; and solo performances on such TV shows as "Deep Space Nine", "Highway to Heaven", and "Dr. Quinn, Medicine Woman".
McNab's motion picture soundtrack credits number over 1,200 from 1970 to the present and his solo trumpet can be heard on such soundtracks as: Dances with Wolves , The Gambler , Avalon , Crimson Tide , City Hall , In Country , Twister , Executive Decision , Independence Day , Con Air , Air Force One , The Postman , U.S.Marshalls , Renaissance Man, Toys, and L.A. Confidential .
Teaching experience at the college level includes positions at U.C.L.A., Cal State Fullerton, Cal State Long Beach, Pomona College and at the Claremont Music Festival. His students have gone into such orchestras as the Houston Symphony and the Boston Pops Orchestra. In addition he has lectured at the International Trumpet Guild an