The bride wore an ivory, above-the-knee dress designed by McCartney's daughter Stella. McCartney wore a dark suit, a somber tie, and a big grin.
The two were wed at Old Marylebone Hall, where McCartney married his first wife, Linda Eastman, in 1969. Eastman later died of breast cancer.
His second marriage in 2002 to model Heather Mills ended in divorce in 2008.
Drummer Ringo Starr, the only other surviving member of the band that rocked the globe in the 1960s, attended the ceremony along with other family and friends.
The former Beatle and Shevell announced their engagement earlier this year. This is Shevell's second marriage. She was married for more than 20 years to attorney Bruce Blakeman and serves on the board of New York's Metropolitan Transportation Authority.
She also is a vice president of a New Jersey-based trucking company owned by her father.
McCartney's Oct. 9 wedding is particularly poignant because Sunday would have been John Lennon's 71st birthday.
In New York City, Lennon fans marked the occasion with a visit to Central Park's Strawberry Fields.
The Associated Press contributed to this report.