In 2001, at the age of 49, he entered politics, contesting for the parliamentary seat of Kabale Municipality.

At the age of 28, in 1908, he successfully contested for the seat in Pembrokeshire and was re-elected continuously until 1918.

In 1982, Ibrahim again contested for the same seat but lost by 100 votes.

In 2008 he contested a by-election for the same seat, but lost his deposit.

After unsuccessfully contesting the 1929 by-election for the federal seat of Franklin, he retired from politics.

He contested the 2004 federal election as the Family First candidate for the seat of Solomon, receiving 2.1% of the vote.

In 1967, he contested as the ALP candidate for the seat of Rodney but was not elected.

In 1880, he unsuccessfully contested for the Parliamentary seat at Falmouth.

Markus contested the 2010 federal election as the Liberal candidate for the seat of Macquarie .

He contested for the parliamentary seat of Lamwo Constituency and was declared the winner in June 2001.