[10] Shelton retired from the Council to contest the 2006 state election, running in the seat of Toowoomba North for the Queensland Nationals.

[16][17] In the Australian Marriage Law Postal Survey, as of mid-September 2017, Shelton was mentioned across news outlets more times than the leading three "Yes" campaigners, Alex Greenwich, Tiernan Brady and Sally Rugg, combined.

[18] In February 2018, Shelton resigned from his ACL position[19] to re-enter party politics, joining Cory Bernardi's Australian Conservatives as federal communications director.

[23] In March 2021, during a Supreme Court case between two factions of the board,[24] Fred Nile announced that he would be stepping down at the end of 2021 and nominated Shelton as his successor in the New South Wales Legislative Council and as President of the NSW Christian Democratic Party.

The Australian Financial Review stated that his priorities were expected to be "abortion, energy security, poverty and “woke corporations”".

Shelton was reported to be "devastated", but pledged "my ongoing service to party members and supporters as we build a political movement that truly reflects Christ's character".

[28][29] Tom Kenyon, a former Labor state minister and the current National Chairman of Family First, said he was 'delighted' to have 'someone of Lyle's calibre' joining the party.

In December 2016, Shelton was awarded the World Magazine's 2016 Daniel of the Year because of his role in the same-sex marriage debate in Australia.