Jill Abramson, who was the New York Times executive editor from September 2011 to 2014, made the remarks while speaking on BBC Newsnight.
She also criticised the Mr Trump’s pick for the US Supreme Court as well as his approach to climate change and healthcare.
When asked if she sees a single redeeming thing about the first year of Donald Trump’s presidency, she said: “The strong economy obviously is a big plus but I do not really think President Trump can take much credit for it.
“If the economy is doing so well, why on earth do we need a big tax cut for the billionaire class?
“I do not see much and I really feel in the past year that, as President, Donald Trump has shown himself as completely unsuitable to the job.”
Ms Abramson also said that she thinks the US’ standing in the world “has been hurt” during the past year.
On the world stage Donald Trump finds himself in a weaker position than his two predecessors as his global approval rating stands at a very low 30 per cent.
Canada, Portugal, Belgium and Norway had the largest decline, with approval ratings in each country dropping 40 points or more.
However, the US President remains positive, tweeting earlier this week: “ISIS is in retreat, our economy is booming, investments and jobs are pouring back into the country, and so much more! Together there is nothing we can’t overcome – even a very biased media. We ARE Making America Great Again!”
The past year has been eventful for Trump as he battled against allegations over connections with Russia as well as escalated rhetoric with North Korea, his healthcare bill.
The Republican also fired the head of the FBI and spark controversy after he announced plans to move the US embassy to Jerusalem.
He is the only US President since Harry Truman to have a negative net approval rating after a year in the White House and finds himself an unbelievable 24 points below where Barack Obama was at the same time in his presidency.
Trump’s honeymoon period did not last long, as eight days after his inauguration he had managed to achieve a majority disapproval rating.
The Republican businessman managed to win the presidency despite being extremely unpopular in many parts of America and was only the fifth US President in history to win despite losing the popular vote, the previous being George W Bush in 2000.
Despite the overall drop in public opinion, Mr Trump’s approval ratings have remained stable since July.
He had a positive net approval rating in 17 states during 2017 – all of which he won in the 2016 presidential election and has regularly outperformed the polls, suggesting he could potentially win another election.