Nathan Elvery joined the authority in June 2016 on £190,000 a year after holding the same role at the London Borough of Croydon.
Accounts show Mr Elvery received £47,500 in the financial year 2016/17 for ‘expense allowances’.
A spokesman for the county council said: “In order to ensure we can appoint candidates with the right skills and experience to deliver the best service for residents we have a competitive recruitment package which includes financial support to attract people from outside of our county.
“This applies to posts which are hard to recruit to and/or where we recognise we need to provide a competitive package to attract the right candidate for our organisation.
“The chief executive post is appointed to by a cross-party panel chaired by the chairman of the county council.”
The figure was discussed by the council’s governance committee on Monday January 22 during an item on its pay policy statement.
This contains a legal requirement to publish pay multiples, which sets out the ratio between the council’s highest and lowest paid employees.
This ratio has risen from 1:11 in March 2016 to 1:13 in March 2017.
Before Mr Elvery’s appointment, the council only had a chief operating officer who was paid less having scrapped the post of chief executive after Kieran Stigant left in January 2014.
James Walsh, leader of the Lib Dem group, suggested the difference between the highest and lowest paid was ‘moving in the wrong direction’, while the £47,500 relocation allowance was a ‘significant addition to the salary’.
He added: “It’s unlikely another member of staff is going to get allowance expenses of that magnitude.”
According to officers the ratio is a comparison of salaries and does not include one-off expenses.
They described how the salaries for chief executives at similar authorities was in the range of £186,000-£230,000 so West Sussex was ‘towards the bottom end’.
Meanwhile the number of senior staff has been reduced.
Sue Mullins, leader of the Labour group, wondered if the ratio could have been affected by low wage increases over the last few years.