The Champion was a streamlined passenger train operated by the Atlantic Coast Line Railroad and Florida East Coast Railway between New York City and Miami or St. Petersburg, Florida. It operated from 1939 until 1979, continuing under the Seaboard Coast Line and Amtrak. It was a direct competitor to the Seaboard Air Line Railway's Silver Meteor, the first New York-Florida streamliner.

The Champion started as a daily service of the Atlantic Coast Line Railroad (ACL) in 1939, competing with the Silver Meteor of the Seaboard Air Line (SAL) on the New York–Florida route. Initially just a New York-Miami service, the ACL added a section serving St. Petersburg and the Tampa Bay area in 1941 once enough streamlined equipment was available. The train was rebranded as the Tamiami Champion, with the St. Petersburg section called the Tamiami Champion (West Coast) (91 northbound/92 southbound), and the Miami section called the Tamiami Champion (East Coast) (1 northbound/2 southbound). In 1943 the names became East Coast Champion and West Coast Champion.

Southbound trains originated in New York's Pennsylvania Station, and traveled south over the Pennsylvania Railroad-owned Northeast Corridor through Philadelphia, Pennsylvania to Washington, D.C. There, a radio-equipped lounge car was added to the train. Leaving Washington, trains used the Richmond, Fredericksburg and Potomac Railroad to Richmond, Virginia, the north end of the ACL's main line. From Richmond, trains followed the Atlantic coast through Charleston, South Carolina and Savannah, Georgia to Jacksonville, Florida. Here the train split, with the West Coast section moving south then west through DeLand and Sanford on ACL rails to St. Petersburg, while the East Coast section turned south south-east to run along Florida's east coast to Miami via the Florida East Coast Railway.

Prior to the Civil Rights Movement, black passengers on the Champion and other trains running through the southern United States were restricted to the "colored" coach, a combination baggage/coach behind the diesel. African Americans ate behind a curtain at two designated tables next to the kitchen of the dining car, but were barred from the observation-tavern-lounge on the rear of the train. Racial segregation on trains serving the South persisted even though the Interstate Commerce Commission (ICC), U. S. courts, and President Harry S. Truman's 1948 mandate (banning segregation in railroad dining cars) had ordered interstate carriers to desegregrate.

By 1955 the West Coast Champion began hauling thru-cars for the City of Miami and South Wind streamliners to and from Chicago on its Jacksonville–Tampa/Sarasota leg via Orlando and its Jacksonville–St. Petersburg section via Gainesville, Ocala and Clearwater. During its long successful career the Champion network reached virtually every major city and resort in the Sunshine State except Florida Panhandle cities like Pensacola and Tallahassee, which were served by Seaboard's Jacksonville–New Orleans overnight Gulf Wind. By the early 1960s the West Coast Champion also had different sections north of Florida: in Wilson, North Carolina a section branched southeast to Wilmington, North Carolina and in Florence, South Carolina a branch left bound for Augusta, Georgia. However, these through services were only offered southbound. By 1966 these Augusta service was offered northbound also. In 1967 these sections to Wilmington and Augusta shifted over the East Coast Champion. The Gulf coast branch lines carried West Coast Champion thru-cars to three different Florida branches, one to St. Petersburg, a second to Tampa, Bradenton and Sarasota, and a third to Fort Myers and Naples. By April 1967 the Augusta branch was switched over to the Everglades and Palmetto trains.

The East Coast Champion ran up and down the Florida East Coast Railway stopping at popular east coast resorts. In 1963 the ACL rerouted the East Coast Champion from the coastal FEC tracks to an interior ACL route through Sanford and Auburndale, a town adjacent to Winter Haven, and then on SAL tracks from Auburndale to West Palm Beach and then to Miami.

At the outset, the Champion was an all-coach streamliner pulled by a diesel electric locomotive. Pullman sleeping cars were added by 1941. One Champion A-unit resides at the North Carolina Transportation Museum in Spencer, North Carolina.

In 1967, the Atlantic Coast Line merged with the Seaboard Air Line to form the Seaboard Coast Line, making the Champion a sister train to its longtime rivals, the Silver Meteor and Silver Star. Additionally, a few months after the merger, on September 4 northbound, and September 5 southbound, the East and West trains were consolidated into one. By December 1967, the name was simplified to the Champion, with the Miami and southeast Florida destinations eliminated, as the formerly SAL trains, the Silver Meteor and Silver Star had those responsibilities. Nonetheless, the Champion continued to have three different sections south of Jacksonville, simultaneously bound for different aforementioned Gulf Coast destinations from the ACL years. The Sarasota section was extended the next year to Venice. The Champion remained as a New York–St. Petersburg service, numbered #91 southbound and #92 northbound.