;Summary of results From its creation in 1950 until 2019,
Labour Party MPs were elected and served the seat, with the exception of the period from 1979 to 1992, which was whilst the
Conservative Party were in government, with a one-year gap caused by a
Labour win at a 1982 by-election. From 1979 to 1982, the MP was
Jocelyn Cadbury, a member of the influential and large Cadbury family. Despite the closure of the Longbridge Motor works the Labour MP at the time,
Richard Burden was returned in the
2005 general election with his majority reduced by 5.6%. He was re-elected with his majority further reduced by 14.1% in 2010. In
2015, Burden was re-elected with a majority of 2,509 votes and a vote share of 41.6%, which made Northfield the most marginal seat in Birmingham and gave the seat the 26th-smallest majority of Labour's 232 seats by percentage of majority. Two years later at the
2017 snap election, Burden increased his majority to 4,667 votes and his vote share to 53.2% on an overall turnout of 44,348 voters. At the
2019 general election, the seat was won by the
Conservative candidate
Gary Sambrook with a majority of 1,640 votes. The Conservatives therefore held the Birmingham Northfield seat for the first time in 27 years. This result was reversed when
Laurence Turner of the Labour Party recaptured the seat at the
2024 general election with a majority of 14.3%. ;Opposition parties The Conservative candidate for 2015, MacLean, came within 5.9% of winning the seat. UKIP's swing nationally was +9.5% in 2015; here it was 13.5%, enabling a third place, having been fifth-placed in the previous election. The other two candidates, standing for parties other than Labour on the
left, narrowly forfeited their
deposits. In 2024,
Reform UK came third with 21.0% of the vote. ;Turnout Turnout has ranged between 84.7% in 1950 and 50.8% in 2024 (which was below the percentage of the 1982 by-election). ==Members of Parliament==