Schiraldi, along with future Boston Red Sox teammate Roger Clemens, pitched the 1983 Texas Longhorns baseball team to a 1983 College World Series championship.

Following his performance in the College World Series, Schiraldi was selected by the New York Mets in the first round (27th pick) of the 1983 Major League Baseball draft.

He made his major league debut on September 1, starting the second game of a double header against the San Diego Padres, and gave up five runs (four earned) in 3.1 innings.

With no outs, runners on first and third, and the Red Sox already down 6-3 to the Seattle Mariners in the Kingdome, Schiraldi replaced Jeff Sellers in the sixth inning.

[6] Whereas closing duties had been split between Bob Stanley and Joe Sambito up to that point, Schiraldi emerged as the Bosox's closer for the remainder of the season.

Mookie Wilson followed by hitting a ground ball that rolled between the legs of Bill Buckner, scoring Knight and giving the Mets an improbable victory.

The Cubs shifted him back to the bullpen in 1989 before sending him to the San Diego Padres just before the August 30 trade deadline, with Darrin Jackson and a player to be named later for Luis Salazar and Marvell Wynne.

Though he did make eight starts with the Padres in 1990 (including the game where Roseanne Barr infamously performed "The Star-Spangled Banner" at Jack Murphy Stadium),[9] he found himself in the bullpen for most of the season.

He was assigned to their triple A Pacific Coast League affiliate, the Tucson Toros, with whom he went 3–2 with a 4.47 ERA before being dealt to the Texas Rangers.

Schiraldi's son Lukas played four years of baseball at St. Michael's Catholic Academy under his father as head coach, and was named to the All-State team as a pitcher his senior season.

[12] Lukas was signed in June 2014 by the Seattle Mariners and played in their minor league system until July 2017, when he was part of a trade to the Miami Marlins for David Phelps.

[13] Schiraldi wrote the book The Arena: The True Story of One Man's Search for Excellence and the Price He Paid for Daring to Achieve It about his upbringing, time spent at the University of Texas, his Major League career and post playing days.