Colin Allred was born in Dallas, Texas, and raised by a single mother who was a public school teacher. He attended Hillcrest High School, where he played baseball, basketball, and football, and served as class president.

Allred played as a linebacker for the Baylor Bears under head coach Guy Morriss. He was selected as the team captain and defensive MVP in 2005. He also received All-Big 12 honorable mention from the Associated Press and was selected as a first-team Academic All-Big 12 in 2004 and 2005.

Allred graduated from Baylor with a Bachelor of Arts in history.

Allred was signed by the Tennessee Titans as an undrafted free agent following the 2006 NFL draft.

Allred was waived by the Titans but re-signed on January 26, 2007. He was waived again on September 1 during final cuts and signed to the practice squad on September 2.

Allred was promoted to the active roster as linebacker and made his NFL regular season debut on December 16, 2007. He played for the Titans between 2007 and 2010, appearing in 32 games and recording 46 tackles.

Allred was severely injured in the neck during a game against the Dallas Cowboys. He subsequently decided to retire from football and go to law school.

Allred enrolled at the UC Berkeley School of Law.

Allred graduated from UC Berkeley School of Law with a Juris Doctor degree.

Allred worked for Battleground Texas as its Dallas-Fort Worth Regional Director of Voter Protection.

Allred worked as a special assistant in the Department of Housing and Urban Development's Office of General Counsel in the Obama administration.

Allred married Alexandra Eber.

Allred announced his campaign to challenge incumbent Republican Pete Sessions.

Allred defeated Lewisville businesswoman Lillian Salerno in the runoff election, receiving 69.5% of the vote.

Allred was elected to the House of Representatives for the 32nd district of Texas, defeating Pete Sessions.

Allred was elected co-president of the Democratic freshmen of the 116th Congress.

Allred and his wife had their first son.

Allred voted for the two articles of impeachment against President Donald J. Trump in his first impeachment.

Allred endorsed Joe Biden after Castro withdrew from the race.

Allred and his wife had their second son.

Allred voted to impeach Donald Trump during his second impeachment following the January 6 Capitol attack.

The United States Chamber of Commerce endorsed Allred in the 2022 House election.

The Common Ground Committee named Allred the most bipartisan member of Congress from Texas.

Allred announced his candidacy for the United States Senate in 2024, challenging Republican incumbent Ted Cruz.

Allred won the primary nomination for the Democratic Party.

Allred lost the general election to incumbent Ted Cruz by 8.6 points.