After graduating from Hood College, he worked as a fourth grade teacher for Frederick County Public Schools from 1983 to 1986.

[1] During this time, Kerr led a group of fourth-graders through the Maryland State House and thought to himself, "Wow, this is really cool.

He declined to request a recount, saying that he trusted the proficiency of the elections officials in tallying absentee and provisional ballots.

[8] During the general election, Kerr teamed up with candidates Michael Bunitsky and incumbent school board member Joy Schaefer to campaign and fundraise together and to pool funds.

[15] After his general election win, Kerr resigned from the Frederick County Board of Education.

[16] The Frederick County Council voted to appoint Lois Jarman to fill his seat.

[31] In March 2019, Kerr voted in favor of legislation that would ban foam takeout containers.

[32] In February 2020, Kerr was one of seven Democrats who voted against a bill that would mandate background checks on private sales and transfers of shotguns and rifles.

[37] In March 2019, Kerr voted in favor of a bill that would allow physicians to prescribe medication to terminally ill people, at the patient's request, to aid in their death.

[39][40] During the 2018 election, Kerr received an A-plus rating from the Maryland Cannabis Policy Coalition for his support of legalizing marijuana.

[44] During his 2018 campaign, Kerr said that people should look at the impact that technology such as autonomous vehicles could have before building more lanes on Interstate 270.