Justice Buch (retd) was sworn in as the anti-corruption ombudsman at a function in Raj Bhavan by Governor Beniwal in the presence of Modi and Assembly Speaker Vaju Vala. (Agencies)
The post had been lying vacant since the last incumbent Justice RM Soni's term expired in December 2003.
The appointment also came at a time when Modi, who is BJP's prime ministerial candidate, was facing flak from Congress over the post lying vacant for a long time.
The Opposition party had said Modi had been repeatedly raising the issue of corruption under the Congress-led UPA government, but failed to appoint Lokayukta in his own state.
Justice Buch said he will act according to the law.
"If the complaints are entertainable within the fixed categories (within the Lokayukta Act), then the complaints would be dealt with accordingly," he said.
"However, if the complaint is beyond the purview of the law, the Lokayukta cannot act," he added.
The Modi government, which had been at loggerheads with the Governor since 2011 over the appointment of Lokayukta, on November 27 recommended Justice Buch's name to the post.
A major controversy erupted when the Governor appointed Justice (retd) R A Mehta as Lokayukta on August 25, 2011, without consulting the state government.
This led to a long-drawn legal battle that reached the Supreme Court, which subsequently upheld the Governor's decision.
Another twist came when Justice Mehta declined to take charge of the office in August this year, citing the long legal battle over his appointment and "the government not accepting his objectivity and credibility."
Leader of Opposition Shankarsinh Vaghela, however, could not attend the function since he said he received the invitation only yesterday just a day before the event.
Justice Buch (retd) was sworn in as the anti-corruption ombudsman at a function in Raj Bhavan by Governor Beniwal in the presence of Modi and Assembly Speaker Vaju Vala.