[1] Late in his career, he developed an old-fashioned, early twentieth-century windup in which he swung his arms back and forth to create deception and momentum.

[4] Byrd attended Louisiana State University where he pitched as part of the Tigers baseball team that won the 1991 College World Series.

[5] Byrd spent the first four seasons of his career pitching in Cleveland's minor league system, reaching Triple-A in 1994.

On November 18, 1994, Byrd was traded to the New York Mets alongside Jerry Dipoto, Dave Mlicki, and a player to be named later (minor leaguer Jesus Azuaje) in exchange for Jeromy Burnitz and Joe Roa.

[6][7] Byrd made his major league debut for the Mets on July 28, 1995, allowing two hits and an earned run in 2⁄3 of an inning in a 10–9 win over the Pittsburgh Pirates.

Byrd parlayed his successful 2002 season into a two-year, $10 million contract with the Atlanta Braves, which he signed on December 17, 2002.

[7] He also made his first postseason appearance for the Braves during the 2004 National League Division Series, recording the loss in Game 3 after replacing an injured John Thomson in the first inning.

[7] On December 14, 2004, the Anaheim Angels signed Byrd to a one-year, $5 million(USD) contract following the trade of right-handed pitcher Ramón Ortiz to the Cincinnati Reds.

[24] In the 2005 American League Division Series, Byrd struggled in Game 3 against the New York Yankees, allowing four earned runs on seven hits in 3+2⁄3 innings pitched, but the Angels managed to win, 11–7.

He went five innings, giving up two earned runs and striking out four, gaining the victory in an Indians 7–3 win to take a 3–1 lead in the best of seven series.

[34] He made his first major league start of the 2009 season on August 30 against the Toronto Blue Jays, tossing six scoreless innings while giving up three hits and three walks.

[38] Rob Manfred, then MLB senior vice president for business and labor, asserted that Byrd did not have a therapeutic use exemption (TUE) as he claimed.

[41] Byrd's wife, Kym, is a certified life coach where she helps married athletes with the rigors of their unique marriages.

[42] Through an organization called CRU, Paul and Kym currently travel to various colleges around the United States speaking to students about "Faith in Sports" and "How to Stay Married in a Career Dominated Lifestyle."

He did on-field interviews and provided analytical color commentary in tandem with the Braves' play-by-play announcer Chip Caray and Jeff Francoeur.