Robert Levinson was a commercial transport passenger in the 24th century.
In 2328, the SS Kogin ferried him from Denkir Orbital City to Janus VI. His special accommodations were a null grav suite and a Class N atmosphere suite. His manifest was accessed by Lieutenant Commander Data aboard the USS Enterprise-D in 2370 by reviewing this data in the commercial transport database. (TNG: "Inheritance", okudagram)
This character was only mentioned in writing.