He was a third round draft pick in the 1984 NFL Draft by Washington after a college career at UCLA, in which he started only one game. He did produce a memorable moment, however, throwing a game-winning touchdown pass on a deflection to future NFL star Freeman McNeil to beat arch-rival USC. He also played minor league baseball in the Pioneer League. Schroeder was pressed into service during his second year after starting quarterback Joe Theismann suffered a career ending leg injury on "Monday Night Football" in the second quarter of the eleventh game of the season against the New York Giants. Schroeder's first pass play after Theismann was taken off the field was a 43-yard completion to Art Monk.  The Redskins came close to a touchdown after the catch, but a fumble by John Riggins inside the five yard line was recovered by Lawrence Taylor. Washington eventually won the game, 23-21 and Schroeder led them to a 4-1 record after that game. He gained the starting spot on the Redskins in his third NFL season, and led them to a 12-4 record while throwing for 4,109 passing yards, which is second best in Redskins history. He managed to lead Washington all the way to the NFC title game, where his team was shut out 17-0 by the New York Giants.
The following season, Schroeder suffered a separated shoulder in the first game against the Philadelphia Eagles and was replaced by Doug Williams. Williams strongly disliked his fellow QB, largely due to Schroeder pointedly waving him off the field when Redskins head coach Joe Gibbs thought Schroeder had been injured and sent Williams in as a precaution. Schroeder returned that season, but was continually nagged by the injury and saw his standing amongst his teammates and coaches fall sharply, allowing the more popular Williams to gain the starting position for the Redskins' playoff run. Williams led the Redskins to a championship victory that year in Super Bowl XXII. Schroeder was traded the following season for Raiders tackle Jim Lachey, who proved to be a perennial Pro Bowl player for the Redskins.
He spent several seasons as the Raiders' starting quarterback, with varying levels of success. He led the Raiders all the way to the AFC championship game as a starter in the 1990 season. However, his team was blown out by the Buffalo Bills 51-3, and Schroeder was intercepted five times during the game. Todd Marinovich replaced him for one regular season and one playoff contest in the 1991 season, and Jeff Hostetler arrived in 1993 after Schroeder was waived.
Schroeder retired in 1995 with 1,426 of 2,808 completions for 20,063 yards and 114 touchdowns, with 108 interceptions, while also rushing for 761 yards and five touchdowns.