As a child Parks acted in the 1956 movie The Swan, which starred Grace Kelly. He also worked steadily on television as a child actor between 1953 and 1958. Early on, Parks also played in the folk group, The Greenwood County Singers with his brother, Carson Parks. After relocating to Los Angeles, Parks then worked as a studio musician and songwriter for Warner Brothers, writing hits for many artists such as Harpers Bizarre ("High Coin"); he became known for his clever lyrical wordplay and sharp imagery. He also played on several important recordings by The Byrds, whose producer Terry Melcher was a close friend of Beach Boys leader Brian Wilson, and this connection led to the meeting of Parks and Wilson in 1965.

In 1966 Parks was commissioned by Wilson to write lyrics for the Beach Boys' next LP, the ambitious but ill-fated Smile project. Parks and Wilson collaborated on the songs for the album. Unfortunately, the Smile project was strongly opposed by members of the Beach Boys (notably Mike Love who negatively called Parks' lyrics "Acid Alliteration"). The combination of resistance from the group and their record company, and Wilson's growing mental health problems and spiralling drug use, led to Parks quitting the project in early 1967 and it was shelved a few months later. Several Wilson/Parks songs from the Smile sessions later appeared on the Beach Boys' replacement album Smiley Smile, including "Heroes and Villains" and "Wind Chimes"; several other songs slated for Smile, including Cabinessence and Surf's Up, were compiled by Carl Wilson and included on subsequent LPs.

Smile soon acquired legendary status as one of the great lost works of the rock era. In 2004 Brian Wilson, now recovered from his mental health problems and having returned to touring and recording, made the surprise announcement that he was finally going to re-record the work using his current touring band. He contacted Parks, the duo finished the uncompleted parts of the album, and it was then recorded by Wilson and his band and released to enormous critical acclaim, earning Wilson a Grammy award for the Best Rock Instrumental Performance for the piece "Mrs O'Leary's Cow" (aka "Fire").

In 1968, Parks released his first solo project, the critically acclaimed album, Song Cycle, a "head trip" of orchestral textures and traditional Americana-meets-psychedelic pop song structures. Song Cycle established Parks' signature approach of mining and updating old American musical traditions, including ragtime and New Orleans-style jazz, with literate, playful lyrics, and is also notable for the inclusion of a cover of the Randy Newman song "Vine Street". Although praised by critics, the album sold extremely poorly.

Four years later, Parks' many travels to the West Indies inspired his second album, Discover America. Among other things, Discover America was a rich tribute to the islands of Trinidad and Tobago and the native Calypso music. Van Dyke Parks was clearly at home re-arranging and re-producing obscure songs and calypso classics. The laid-back tropical feel of the songs and production made Discover America a fan favorite.

Parks' 1984 album Jump featured songs centered around the tales of Uncle Remus and Brer Rabbit. Jump solidified Parks' reputation as a pop songwriter with some childlike tendencies. Production on the album was slick and the sound was focused and cohesive.

Following Jump, in 1989 Van Dyke Parks released the ambitious Tokyo Rose. The album tells tales of Japan and U.S. relations in the early part of the 20th century. Growing from the "children's song" feel of Jump, Tokyo Rose was an orchestral album with more mature subject matter. The songs were pop tunes with the signature Van Dyke Parks chord changes and mind-bending melodies. His earlier-developed sound of orchestra meets pop song meets female background vocal choir continued to develop on Tokyo Rose. The sound was lush and orchestral and took the listener on a journey from old Tokyo to the Wild Wild west on fan-favorites such as "Tokyo Rose", "Cowboy", "Manzanar" and "White Chrysantemum".

In 1995 Parks teamed up again with Brian Wilson, this time to create the album Orange Crate Art. Parks wrote all of the songs on the album, save "This Town Goes Down At Sunset" and George Gershwin instrumental "Lullaby", and the vocals were done by Brian Wilson. Orange Crate Art is a harmonic tribute to the Southern California of the early 1900s. The songs are rich and lavishly orchestrated.

Parks has produced, arranged, or played on albums by artists including U2, Randy Newman, The Byrds, Cher, Rufus Wainwright, Sam Phillips, Ringo Starr, Keith Moon, silverchair, Carly Simon, T-Bone Burnett, Toad the Wet Sprocket, Victoria Williams, Bonnie Raitt, Peter Case, Gordon Lightfoot, Fiona Apple, Sheryl Crow, Ry Cooder, The Everly Brothers and The Esso Trinidad Tripoli Steelband.

Parks has also scored a number of motion pictures, including Jack Nicholson's The Two Jakes, Casual Sex, Private Parts, Popeye (with Harry Nilsson ), and The Company. Disney also hired Parks to arrange Terry Gilkyson's Academy Award nominated song "The Bare Necessities" for the 1967 feature The Jungle Book.

Though he has done so with far less frequency in recent years, Parks has occasionally taken small TV and film roles, including appearances in Popeye, The Two Jakes, and the Twin Peaks TV series.