McDonald transferred to California University in 2012 after playing three seasons at Fairmont State University in Fairmont, West Virginia. After missing the 2012 season due to injury, he was a senior captain for the Vulcans in 2013. In his senior year, he recorded 89 tackles and returned all three of his interceptions for touchdowns. His three interception returns for touchdowns made him the first Pennsylvania State Athletic Conference player to accomplish the feat in over 10 years.
Professional career
Indianapolis Colts
McDonald signed with the Indianapolis Colts as an undrafted free agent after the 2014 NFL Draft. After starting the 2014 season on the team's practice squad, he was signed to the active roster on September 29. He appeared in 12 games during his rookie season, recording 10 tackles, including 8 solo. He also appeared in three playoff games for the team that season, recording one tackle in each. On September 5, 2015, McDonald was waived by the Colts. He was added to the practice squad the following day. He was elevated to the active roster on October 20. He appeared in one game and recorded one tackle. On October 27, 2015, McDonald was waived by the Colts to make room on the active roster for Quan Bray.
On October 28, 2015, McDonald was claimed off waivers by the New England Patriots. He played one game with the Patriots before being waived on November 12. He was signed to the team's practice squad on November 14, but was released four days later. The Patriots signed McDonald to the active roster on November 26, 2015, after placing Aaron Dobson on injured reserve. On November 28, 2015, he was waived once more.
Oakland Raiders
On December 2, 2015, McDonald was signed to the Oakland Raiders practice squad. On December 29, he was elevated to the active roster for the team's final game of the season after fullbackMarcel Reece was suspended.
Seattle Seahawks
On September 3, 2016, McDonald was traded to the Seattle Seahawks in exchange for a conditional pick in the 2017 NFL Draft. The Seahawks converted McDonald from a safety to a linebacker. He played in 14 regular-season games in the 2016 season, recording 8 tackles, along with two playoff games. On September 27, 2017, McDonald was placed on injured reserve after suffering an ACL injury in Week 3.
Career statistics
Regular season
Postseason
Personal life
In 2015, McDonald started a foundation to help his youth Jefferson County, West Virginia. He started his own flag football league, called the Dewey League, and charity softball tournament.