In 1876, in a 20-foot (6.1 m) sailing dory, he made the first recorded single-handed crossing of the Atlantic Ocean, landing at Abercastle in west Wales as a celebration of the first centennial of the United States.

[1] Local author Rob Morris has written a book about the crossing called Alfred "Centennial" Johnson.

It is frequently displayed alongside Howard Blackburn's sloop Great Republic, a vessel which was also used in a single-handed trans-Atlantic crossing.

He had run away to sea as a teenager, and after working on sailing ships eventually ended up as a fisherman in Gloucester, Massachusetts.

Johnson planned to carry out his voyage as a celebration of the first centennial of the United States; his aim was to sail to Liverpool, hoping to make the 3,000-mile journey in under 90 days.