Sheinwold was born in London, England and emigrated to the United States as a young man. He soon became well known as a bridge writer and editor, and started work as an editor for Ely Culbertson's magazine The Bridge World in 1934, where he held the posts of technical editor, then managing editor, and then senior editor. After Edgar Kaplan purchased The Bridge World, Sheinwold became one of four expert members on the rotating directorship of the Master Solvers Club, from 1967—1980. Sheinwold occasionally wrote Bridge World articles under the pseudonym Saxon Fairwood (Saxon for the Anglo-Saxon King Alfred; Fairwood as a pseudo-translation of "Schein Wald," sunny (or fair) for Schein, wood for Wald).

During WWII, Sheinwold interrupted his bridge career to serve as Chief Code and Cipher Expert in the Office of Strategic Services for the United States.

During the period of the development of the Kaplan-Sheinwold bidding system, Sheinwold was particularly successful in national level tournament bridge in the United States. He won the Chicago event (subsequently known as the Reisinger) in 1958 and the Spring National Men's Teams in 1964, was on the runner-up team for the Vanderbilt (also 1958), and had many regional wins.

Sheinwold is credited with the following at-the-table play, reprinted by José Le Dentu:

South, Sheinwold, played 6. West led the 5 and East followed suit with the 2 as Sheinwold let dummy's J win. To cater for a 4-2 break in both red suits, Sheinwold led dummy's 2 (!) to the second trick.

Now, Sheinwold could subsequently take dummy's Q, ruff a low diamond, pull trumps and get to dummy with the K to run the diamonds. The likely 4-2 diamond split means that playing even one top diamond before ruffing a low one upsets the communication between the two hands: this forces declarer to rely on a spade finesse or a low-percentage throw-in.

Sheinwold was often sought as captain by US teams that were pursuing national and international championships. He captained the 1985 US team that won the Bermuda Bowl, and also the 1975 US team that placed second in the same event, one that was marred by scandal.

Sheinwold had written an article prior to the 1975 Bermuda Bowl, published by Popular Bridge, that predicted that the Italian Blue Team would not play as effectively once bidding screens were in place. However, in a different article, he also stated that he did not question the honesty of Italian bridge experts. The Italians were of course upset by the former, notwithstanding the apparently contradictory latter.

It was particularly unfortunate, then, that an American newspaper reporter saw one member of an Italian pair, Facchini and Zucchelli, tapping his partner's feet with his own in a suspicious manner. Impartial observers from the World Bridge Federation (WBF) were brought in and confirmed the behavior. After deliberation by the tournament officials, the players in question were severely reprimanded but allowed to continue in the tournament.

In protest, the American team threatened to withdraw from the tournament — the final — if forced to play against the Italian pair, unless ordered to do so by the ACBL. They were ordered to play, as most, including themselves, anticipated they would be. The Italians prevailed over the Americans in the finals.

After initially hearing of the allegations regarding the Italian pair, Sheinwold had to make a difficult decision as to informing Lew Mathe, at the time the President of the Board of Directors of the ACBL. Sheinwold decided to defer informing Mathe, so as not to compromise the investigation. After learning of Sheinwold's decision, the Board removed Sheinwold from a panel of future captains and publicized that action in a fashion that many at the time found petty. Sheinwold then resigned as Chairman of the ACBL's Laws Commission.

Sheinwold was vindicated in 1977 when, during an affair involving cheating allegations against an American pair, Richard Katz and Larry T. Cohen, Mathe spoke in public regarding supposedly secret negotiations. The Bridge World wrote at the time:

"A member of the ACBL Board apologized to Freddy Sheinwold for having criticized team-captain Sheinwold's failure, in the Bermuda scandal of '75, to notify Mathe, then League President, immediately after hearing about the Italian pair. 'You were 100% right not to tell him', the Board member said ruefully."

Sheinwold may be best known for his syndicated newspaper column, which ran for more than 30 years. (Frank Stewart, Sheinwold's collaborator for several years, took over the column following Sheinwold's death.) But he also prepared the AutoBridge hands and discussions, and authored Five Weeks to Winning Bridge, which sold more than a million copies — phenomenal sales for a book on a card game. He was principal author of The Kaplan-Sheinwold System of Winning Bridge, the first extended description of the Kaplan-Sheinwold bidding system. Sheinwold's smooth, encouraging writing style made him the most popular bridge author of his time.

Sheinwold died of a heart attack in Sherman Oaks, California at the age of 85.

Honors

• ACBL Hall of Fame 1996
• ACBL Honorary Member of the Year 1983

Awards

• Romex Award (Best Bid Hand of the Year) 1995 (Winning Journalist)

Wins

• North American Bridge Championships (2)
• Chicago (now Reisinger) (1) 1958
• Men's Board-a-Match Teams (1) 1964
• Other notable wins:
• Goldman Pairs (1) 1955

Runner-ups

• North American Bridge Championships (2)
• Vanderbilt (1) 1958
• Master Mixed Teams (1) 1959